Cirrus 6.0.2 user manual english dr.boonsong

User Manual

Cirrus HD-OCT

■ Models 400, 4000

Cirrus HD-OCT User Manual 2660021146510 A

Introduction 1-7

Cirrus HD-OCT System Hardware

With the exception of the keyboard, mouse and printer, the Cirrus HD-OCT integrates allhardware components in a unit, which includes the scan acquisition optics, theinterferometer and spectrometer, the system computer and video monitor. Carl ZeissMeditec offers an optional wheelchair accessible motorized power table (shown below),which accommodates elevation adjustment to each patient's height. The illustration belowlabels hardware elements. System specifications are in Chapter (12).

Figure 1-1 Cirrus HD-OCT system hardware

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1 3D Motorized Patient Alignment Unit 8 Media/USB Port

2 Dual Chin Rest with Automatic Right/Left Sensors 9 Table Height Controls

3 Imaging Aperture 10 Mouse

4 Head Rest 11 Keyboard

5 Port for External Fixation Arm 12 System Power Switch

6 Integrated Video Monitor 13 (Optional) Power Table

7 Connectors (USB, network, etc.) and labels underrear cover


Acquire Scans 3-5

Add New Patient Tab

To add a new patient, click the Add New Patient tab and fill in at least the requiredfields, which are indicated in bold type.

Figure 3-3 Add New Patient tab of the ID Patient Screen

Note: The date of birth must be entered in the correct format that matches your Windowsregional settings, and always appears this way in the software and printouts.

• If you want to enter additional information, click More and continue. The Patient Editdialog will appear. For details, see Edit Patient Record on page 8-15.

• A Patient ID is required for all patient files. No patient data can be saved without apatient ID. If you choose not to assign an ID, you may click on Generate ID to have thesystem create a unique ID automatically for this patient. Patient ID’s generated byCirrus all start with the prefix “CZMI”. Because a Patient ID is required forDICOM-compliant import and export of patient data, the system also creates a uniquePatient ID when you export data for any patient that was created without a Patient ID(under previous software versions).

• Entering Patient Refractive Error: You may enter the refractive error in sphericalequivalents for each eye on the patient demographic entry screen if desired. If youhave entered a refractive error for a patient, the instrument will automatically set thefocus based on this information when you advance to the acquisition screen. You maynot need to use the Auto Focus feature if you entered a refractive error. You may needto use the focus arrows to manually adjust the focus for optimal clarity.

• The Cirrus HD-OCT instrument has two Normative Databases to which you maycompare your patient’s scanned data. The original database is called the DiversifiedDatabase (see Appendices D, E, and F for more information). An additional database,the Asian Normative Database (see Appendix G) is also available as a separately


Acquire Scans 3-9

• Anterior Segment Cube 512x128.• 5 Line Raster: The original version of the 5 Line Raster with less resolution than the HD

5 Line Raster.

Before the patient puts his or her head in the chinrest, click to select the desired scan typefor either eye. The automated chinrest will go to the default position for the selected scantype and eye. Proceed to Acquire Scan below.

Preparing the Patient for the Exam Experience

The patient’s exam experience with the Cirrus HD-OCT is normally brief and comfortable.An experienced operator can acquire several scans from each eye in the space of 5-7minutes. An exam usually requires the patient to look inside the imaging aperture for 1-3minutes at a time for each eye, depending on the number of scans desired. The instrumentacquires most scans in about two seconds. The additional time is required to align thepatient before scanning and to optimize scan quality. The patient need not remain in thehead rest between scans since the operator can reposition the head rest as needed. Notethat the Cirrus HD-OCT is never to contact the patient's eye.

Note: It is not necessary for the patient to put their head on the chinrest until after thedesired scan type is selected. If you are using the Repeat Setup (see page 3-28) feature ona patient, the patient must wait until the Repeat Setup function has been selected and thechinrest motions are complete before placing their head in the chinrest. Reducing theamount of time the patient spends in the chinrest improves patient comfort.

Optional Dilation of Patient’s Eye(s)

The minimum pupil size for Cirrus HD-OCT is 2mm. This can usually be achieved withoutdilation. If dilation is performed on a subject for an exam, we recommend that dilation beused on subsequent visits if quantitative comparisons will be made. Dilation should notdirectly affect the quantitative measurements, but it may affect them indirectly by allowingmore variability in how the OCT beam enters the eye. Although such an effect should besmall, optimal repeatability will be achieved by imaging the patient in the same way atevery visit.

Select the Fixation Method

Cirrus HD-OCT provides for internal fixation as the default method. This method is preferredfor its reproducibility and ease of use. However, if the patient’s visual acuity in the subjecteye precludes internal fixation, you have the option of attaching and using the externalfixation device, which is a light-emitting diode on the end of an adjustable arm. Plug it intothe port on the top of the instrument, and position the arm manually in the desiredposition.

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What the Patient Sees

Model 4000 Instrument

Before scan acquisition, the patient looks into the imaging aperture and sees a greenstar-shaped target against a black background. When scanning starts, the backgroundchanges to a bright, flickering red, and the patient may see thin bright lines of light, whichis the scan beam moving across the field of view. Normally, the patient can look inside theimaging aperture for several minutes at a time without discomfort or tiredness.

Note: Instruct the patient to look at the center of the green target, and not at the movinglights (the scan beam).

Model 400 Instrument

Before scan acquisition, the patient looks into the imaging aperture and sees a greenstar-shaped target against a black background. At the same time the patient will see thinbright lines of light scrolling from the top of the screen to the bottom, which is the scanbeam moving across the field of view. Normally, the patient can look inside the imagingaperture for several minutes at a time without discomfort or tiredness. When scanacquisition starts, the patient may notice the thin, bright red lines of light scrolling moreslowly and in some cases at a different angle.

Note: Instruct the patient to look at the center of the green target, and not at the movinglights (the scan beam).


Acquire Scans 3-11

Acquire Scan

When you select Acquire in the previous screen, the ACQUIRE SCREEN appears. The examplebelow shows a Optic Disc Cube 200x200 scan.

Figure 3-7 Sample Acquire Screen

All screen features are the same for all scan types, except that there will be one or fiveviewports in the scan display for the HD 5 Line Raster scan. Beneath the scan list, thescreen is divided into three working areas:

• The iris viewport is at upper left, where you see a live video image of the iris and pupil.You use this to center the scan beam through the pupil by clicking on the pupil centerand/or using the X-Y and Z controls to the right. (X means left and right; Y means upand down; Z means forward and back.) The circular X-Y control is for centering thepupil; it provides 8 directional options for moving the chinrest. The Z controls(left-right arrows or mouse scroll wheel) help you to reach the proper working distance

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1 Patient information 8 Scan display and controls

2 OD Scan List 9 Controls for Reset Scan, Target Placement, adjust 5 Line Raster scans, Focus, Videoand Overlay Transparency, Optimize and Capture Buttons

3 Click to select type 10 Click to drag fixation target or scan pattern

4 Current Eye indicator 11 Fundus Viewport with scan overlay and controls

5 OS Scan List 12 Iris Viewport and controls and Repeat setup

6 Menus 13 Click pupil center to align eye

7 User name

X, Y and Z Controls Explained

X, Y and Z refer to plane of motion.X means left and right movement.Y means up and down movement.Z means forward and back movement.


Acquire Scans 3-13

You will begin to see an iris image once the patient is positioned in the chinrest (althoughthe image may be poorly resolved until properly focused). Alignment progresses through aseries of steps, although the order in which many of the steps are performed (and whetherthey are repeated) will vary depending on the cooperativeness of the patient (e.g., whetherpatients can fixate steadily at a requested location, opacity of their eye, etc.). In general,the sequence of user steps for non-repeat visits is as follows.

Align Eye Using Iris Viewport

1. Adjust the region of the iris visible in the iris viewport. Typically, you will make coarseadjustments using the X-Y controls (that move the chinrest) as needed until the pupil isvisible.

2. Focus the iris image using the controls to the right of the viewport. For focusing, youwill primarily use the Z controls. The mouse scroll wheel works well for fineadjustments. Try to get the iris as clear as possible before proceeding to the next step.

Figure 3-8 Iris viewport

3. Center the pupil in the iris viewport by clicking the center of the pupil. (Clickinganywhere in the iris viewport centers the field of view of the camera over the clickpoint). The centering target overlays the video image. It remains in the center of theimage and illustrates the path of the scan beam.

Note for the Model 4000 only: You may see a reflection of a rectangular band over thepupil, as seen in Figure 3-8 above. This artifact has no significance.

✐ Repeat Setup Button: The Repeat Setup button is available if you havesaved from a previous visit the same scan type for this patient and eye. ClickRepeat Setup to repeat the chinrest alignment and other parameters usedthe last time you acquired this scan type on this patient and eye during aprevious visit. This should get you close to the correct alignment for thecurrent scan, although you still may have to make small adjustments. SeeRepeating Scan Setup and Alignment on page 3-28.

Click pupil center to align

Z Controls

X-Y ControlsAlign

FocusCentering target showspath of scan beam

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Options and Reset buttons

The iris viewport area has a pair of buttons. The Options button opens to additionalcontrols, which allow adjustment of the image settings for that viewport. These controlsalter contrast (left vertical slider), brightness and illumination (right vertical slider). The areaalso has a Reset button , which resets the chinrest position to default. The resetbutton within the options screen resets the contrast, brightness, and illumination.

Place Scan Using Fundus Viewport

1. Focus fundus viewport: The Auto Focus button will attempt to compensate for thepatient’s refractive error by automatically changing the focus adjustment. This mayhelp clear up a dim fundus view and will also help clear up the fixation target for apatient whose refractive error is considerable. In addition to improving the overallfocus, the Auto Focus feature will do an additional adjustment on the brightness andcontrast of the fundus image.

The focus arrows allow you to manually compensate for the patient’s refractive error.Click the left arrow to add minus (-) power to compensate for myopic corrections;click the right arrow for adding plus (+) to compensate for hyperopic corrections. Ask-ing the patient if the fixation target has cleared up after making a focus adjustmentcan help in some cases. When optimized, these focus settings will be retained andcan be used in the future via the Repeat Setup button.

Figure 3-9 Fundus viewport

Note: Ask the patient to hold their gaze and head steady during Auto Focus, as thechinrest assembly moves during this procedure. After Auto Focus, it may be necessary tocheck the Iris Viewport to ensure that the pupil is still centered. If the fundus viewport turnsdark following Auto Focus, center the pupil, click , then click the Auto B/C button. Ifadditional brightness and contrast changes are necessary, use the appropriate slidercontrols (page 3-15).

Click and drag scan pattern and/or fixation target to adjust their placement. Double-click on the point you wish to center. The fixation target moves accordingly.

Auto Focusand Z focus controls

Overlay Transparencycontrol for repeatscans


Acquire Scans 3-15

2. (Optional)–Adjust scan pattern placement: To do this, move the mouse so the cursorhovers within the space of the scan pattern or the alignment target. The cursor willturn into a move symbol. Hold the left mouse button down and drag the mouse tocontrol the position of the scan pattern box. Release the mouse button to set the scanpattern in its new position. If the cursor hovers over the fixation target icon, the cursorturns into a hand with a pointing finger. For the Model 400 instrument, when movingthe scan pattern box, the Live OCT Fundus technology view also moves with the scanpattern box.(Optional)–Adjust region of view: There are a number of ways to adjust the region ofthe fundus image visible within the fundus viewport. You can change the patient’sfixation by either double-clicking anywhere on the fundus image to bring that pointinto the center of view, or click and drag the fixation target. In either case, instruct thepatient to follow the fixation target, which has the effect of changing the region ofview. It is desirable to center the area of interest in the field of view so that you alwaysare scanning the deepest part of the bowl of the retina, which helps maintain the scanimage in the vertical center of the display.To reset either the scan pattern or the fixation target that had been moved from thedefault position, press the appropriate button below:

• Reset scan pattern

• Reset fixation target

Note: If you adjust the scan pattern placement, check the OCT scan display at right tomake sure that the retinal images are not too high in the viewport. When the edges of scanimages are near the upper boundary, they tend to “fold over,” reflecting a “mirror image”back into the viewport. If this occurs, or if the scan image is completely inverted, you mustadjust the image using the Optimize button or Center controls. See Optimize the ScanDisplay on page 3-17.

Note: For Optic Disc Cube 200x200 scans, it is not necessary to precisely center the opticdisc in the scan image because the analysis algorithm can correctly place the CalculationCircle around the optic disc even when it is not well centered. Though it is sufficient to keepthe optic disc within the outer dashed circle, it is best to center the scan on the optic discas well as possible.

Options and Reset buttons

The fundus viewport area has a pair of buttons. The Options button opens toadditional controls, which allow adjustment of the image settings for that viewport. Thesecontrols alter contrast (left vertical slider) and brightness (right vertical slider). An exampleappears at the left for the fundus image. The area also has a Reset button , whichresets the focus position to default. The reset button within the options screen resets thecontrast and brightness.

In addition to the contrast and brightness controls, the fundus image options window alsocontains these features:

When you mouse over the fixationtarget or the scan pattern, thecursor becomes a hand or movesymbol, indicating that you canclick and drag to move it.

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Select Auto B/C to have Cirrus automatically adjust the brightness and contrast levelsof the fundus image.

An optional Show Alignment checkbox is available among the Fundus Image options.For either Macular Cube Scan, this checkbox toggles display of an alignment tool thatis locked in position relative to the scan pattern; the alignment tool moves when youmove the scan pattern and vice versa. This tool is designed to be placed over the opticdisc to assist in accurately repeating scan pattern placement for future scans of thesame eye. For macular scans, placing the alignment tool over the optic disc results inthe scan center being within 1 mm of the fovea for most patients. This tool is helpfulwhen the fovea is difficult to find in extreme edema, cataract, or floater situations. Foroptic disc scans, the alignment tool is centered on the scan pattern and on by default.

Figure 3-10 Fundus images showing alignment tools: Macula and Optic Disc

Note for the Model 400 only:

The Live OCT FundusTM view can be seen in Figure 3-11. For patients with unsteadyfixation, you may change the rate in which the screen refreshes by right-clicking on theimage and selecting Rapid Refresh View. When moving the scan pattern box, the Live OCTFundus technology view also moves with the scan pattern box. You may also select AutoB/C from the same right-mouse click menu as shown on the left.

Figure 3-11 Standard viewport on the Model 400

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• Corneal opacities may be minimized by realignment of the pupil.3. The OCT scan: To optimize signal strength for the best possible OCT images, follow

these guidelines:

• Center the OCT scan in the mid to upper part of the scan acquisition screen. Clickon Optimize or Center to aid in placement.

• The OCT B-scan should be complete in all windows without missing data.• A tilted retina may be corrected for by moving the pupil alignment off-center to

allow for a more level OCT scan.• Media opacities may be minimized by searching different pupil positions for the

brightest OCT image.

• Adjust the enhancement setting to achieve the brightest and clearest scan.

• Ask the patient to blink once before obtaining the scan. Patients with severe dryeye should use artificial tears prior to scanning.

Obtaining Images Suitable for Advanced RPE Analysis

In order to detect sub-RPE illumination, Cirrus looks for contrast in a slab created belowthe RPE. If the retinal tissue is captured too low in the axial field of view of the scan, thenthe algorithm will not produce a good result, because there will not be enough sub-RPEpixels to create good contrast. See the figure below for an example of a scan with sub-RPEillumination, with the retina too low in the scan for acceptable detection of sub-RPEillumination. If you obtain an image like this, it is best to retake the scan before runningAdvanced RPE Analysis (see Chapter 4).

Figure 3-12 Example of Scan with Retina Too Low in Field

Capture the Image

Briefly review the scan windows as described in Criteria for Reviewing Good QualityCirrus HD-OCT Scans on page 3-27. Click Capture—or press Enter on the keyboard—to capture the images. The REVIEW SCREEN appears automatically to display the capturedimages.


Acquire Scans 3-19

Review Scan and Save or Try Again

Review the captured data to ensure it is of acceptable quality. See Review Screen onpage 3-22 and Criteria for Reviewing Good Quality Cirrus HD-OCT Scans onpage 3-27 for more information.

Note: Besides the observed image quality, an important element of acceptable quality isthe Signal Strength indicator, which should be 6 or higher.

Note: Signal strength and image quality can be significantly reduced when the imagingaperture (the lens) is dirty or smudged. If you suspect this problem, follow the instructionsto clean The Imaging Aperture (page 11-6).

If the captured scan is of good quality, click Save and continue. (You will return to theACQUIRE SCREEN to acquire another scan, if desired.) If it is not, click Try Again to return tothe ACQUIRE SCREEN.

When you are finished acquiring scans, click Finish in the ACQUIRE SCREEN. You will return tothe ID PATIENT SCREEN.

Acquire Screen, HD 5 Line Raster

From the Acquire Screen, select scan type HD 5 Line Raster, as shown in Figure 3-13. Theoperation of the HD 5 Line Raster scan is identical to the operation of the original 5 LineRaster scan.

To access the HD Single Line scan, select the button, which is located below thefundus image at the bottom of Figure 3-13. Clicking this button will create the setting toacquire the HD Single Line scan. The button can be used to toggle between the Single andthe 5 Line modes.

Figure 3-13 HD 5 Line Raster Acquire Screen

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The toggle button remains available until the Single Line scan pattern is moved within theacquisition window. To move the scan pattern and keep the toggle button active, toggle to5 Line mode before moving the scan pattern, then switch back to Single Line mode. If youmove the Single Line pattern and want to switch back to 5 Line mode, use the scan patternsettings button, , to access full controls.

Note: By default, all screens associated with the HD 5 Line Raster and HD Single Line scansdisplay the scans in color. However, switch to black and white to assist in showing theadditional resolution gained by using the HD scans. Adjustments to brightness andcontrast as well as switching the scans to black and white images are available using theexisting menus.

Enhanced Depth Imaging (EDI)

Enhanced Depth Imaging is an optional mode for the HD 5 Line Raster scan pattern.

The signal to noise ratio in OCT scans varies across the axial range. The default Cirrus setupis such that the best signal is obtained at the top portion of the scan. Enhanced DepthImaging allows you to change the acquisition settings for the HD 5 Line Raster so that thebest signal to noise ratio is obtained at the bottom of the B-scan. This allows you to obtainan HD image that is optimized in the region that is of interest for a particular scan.

You can toggle between this scanning mode and the standard scanning mode while on theacquisition screen. The scan will be optimized for the bottom half of the screen.


Acquire Scans 3-21

Acquire an HD 5 Line Raster Scan Using EDI Mode

Figure 3-14 Enhanced Depth Imaging Acquire Screen

1. Select the HD 5 Line Raster from the scan selections.2. Align the iris image and focus the fundus.3. Choose the length, distance, and angle of the scan desired using the icons located

under the LSO image.4. Click the EDI button.5. Adjust the scan by using the icons on the LSO screen image.6. Center and enhance the OCT image until you have an acceptable scan fundus and

scan quality.7. Click on the Capture button, review and Save.

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Review Screen

After you acquire a scan, the REVIEW SCREEN appears. The REVIEW SCREEN format depends onwhich scan type you have acquired.

Review Screen for Cube Scans

Figure 3-15 Review Screen for cube scans

For cube scans, the REVIEW SCREEN presents the captured iris and fundus images, along withan interactive multi-planar reformat (MPR), which enables you to view imagecross-sections through two dimensions. The exam protocol (ALL SCANS) appears at topleft, with the eye and name of the scan type below it. The example above is for a MacularCube 512x128.

• Signal Strength Indicator: This appears in the center near the top. It ranges from 0-10,with 10 being maximum signal strength. When values are less than 6, the indicatorcolor is red (below acceptable threshold); when 6 or higher, the color is green(acceptable). Click on the Information button for additional suggestions on how toobtain better signal strength.

Note: The Signal Strength indicator applies to the scan as a whole.

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1 Current X slice through front (fast B-scan)

2 Current Y slice through side (slow B-scan)

3 X slices through front and back (fast B-scans)

4 Fundus image with scan cube overlay

5 Frozen iris image


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• Overlay Options: You can select OCT (default) or None in the Overlay drop-downmenu. The OCT overlay is an en face OCT scan image of the scanned area. (En face,from the French, means literally, “on the face;” that is, looking directly into the eye,which is the same perspective as the fundus image.)

• Transparency Slider: The Transparency slider is present when the OCT overlay isselected. Use the Transparency slider to adjust the transparency of the overlay. Defaultis 0% transparency (opaque); 100% is fully transparent.

• Snap To Center Button: The Snap to Center button is present when the OCT overlay isselected. Click Snap to Center to return the slice navigators (see below) to their defaultcentral positions.

Reviewing Image Data using Multi-Planar Reformat (MPR)

• The viewports are interactive: Click and drag the triangles or click on a scan viewportand use the mouse scroll wheel to “move through” the active plane of the viewport;you will see the resulting cross-sections update simultaneously in the other viewports.This functionality enables you to quickly search through the data cube and stop whenyou see an area of interest.The upper left viewport shows the frozen iris image, while the lower left shows thefundus image with the high definition en face scan image overlay that shows the areascanned. Note that the Model 4000 instrument displays the LSO fundus image, whilethe Model 400 instrument displays the captured Live OCT Fundus technology image.

Figure 3-16 Fundus Image with Overlay in Review Screen

The overlay also has two lines that are centered by default, called slice navigators. Theselines indicate the currently selected cross-sections (slices) seen in the upper two viewportson the right. The horizontal blue line in the overlay corresponds to the top scan viewport,which presents the fast B-scan. The vertical magenta line in the overlay corresponds to themiddle scan viewport, which presents the slow B-scan. You can drag these slice navigatorsby the triangles on the edge to change the currently selected slices.

To better understand the perspectives, think of the data as a cube. The top and middle(larger) viewports show the data in planes parallel to the front of the cube and the side of

En Face Explained

En face, from the French, meansliterally, “on the face;” that is,looking directly into the eye,which is the same perspective asthe fundus image.

Drag triangles on slice

indicate current fast B-scan(X slice) seen in

Front of cube =fast B-scan plane

Top of cube =en face image

slow B-scan plane

blue line

magenta line

Side of cube =

Data Cube Orientation

middle viewport

upper viewport

top scan viewport

Blue line & slice number

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Z

navigators to changecurrently displayed slices

slow B-scan (Y slice) seen in middle scan viewportMagenta line & slice number indicate current

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the cube, respectively. The X slice parallel to the front of the cube (top viewport) is alsoknown as the fast B-scan because this is the direction in which each line of A-scans isacquired extremely quickly (in milliseconds). (This is the direction of a horizontal line scanin first-generation OCT.) The Y slice parallel to the side of the cube (middle viewport) is alsoknown as the slow B-can because this scan comprises a reformatting of vertically parallelA-scans acquired in successive line scans. These re-combined lines are acquired relativelyslowly, one per line of horizontal A-scans, in comparison to the fast B-scans. The smaller,bottom two scan viewports are static and show the front and back X slices of the cube.

Scan Display Left to Right Orientation

Cirrus always displays left to right scan images as follows:• For horizontal scans, left of scan equals left of scan display and right of scan equals

right of scan display.• For vertical scans, bottom of scan equals left of scan display and top of scan equals

right of scan display.• For diagonal scans in 5 Line Raster, left takes precedence over bottom, so that left of

scan equals left of scan display and right of scan equals right of scan display.

Image Display Options During Review

Right-click on the fundus image, on its overlay, or on a scan image to access the imagedisplay options seen in the menu at left, or a subset of them. A checkmark indicates whenan option is selected.

• Normal: Selected initially, clicking Normal exits other display-change modes, andthereby fixes or freezes the changes you have made to that point.

• Reset: Resets the current display to default settings.• Zoom: Gives access to the following options:

• Zoom/Unzoom (toggle)

• Rectangle: When selected, click and drag toselect a rectangular area to fill the screen.

• Continuous: When selected, click and drag up to increase the zoom; click anddrag down to decrease the zoom.

• Pan: This option is present only when the image is zoomed. When selected, click anddrag the image to view other parts of it.

• Full screen: Select to view the image in full screen.

✐ Tip: You can also double-click any image to open it in full screen.Double-click a full-screen image to return to normal view.

• Save image as...: Saves the current image on screen in the location you select.• Brightness/Contrast: When selected, the brightness (B) and contrast (C) values appear

numerically on the image; moving the cursor horizontally changes the contrast (noise)and vertically changes the brightness (OCT color range). They also work incombination when you move the mouse diagonally.

Left to Right Scan Display Summarized

For horizontal scans, left equalsleft and right equals right. Forvertical scans, left to right equalsbottom to top. For diagonal scans,left takes precedence over bottom.


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Brightness and Contrast can be adjusted in two different screens during theacquisition process: On the acquisition screen and on the review screen.

• Acquisition: When you enter the acquisition screen for the first time,Brightness/Contrast for both fundus and OCT images are set to a default values.These values may be adjusted manually or by Auto Focus and Auto B/C (fundusviewport only), as desired.

Any user-initiated changes made on the acquisition screen become the new instrumentdefault settings, which are persistant for all new scans for all operators until the settingsare changed again.

• Brightness/Contrast values adjusted in scan review for both fundus and OCTimages are saved and later used when displaying those images during analysis.Note: Cirrus may override adjusted extreme values that could compromise imagequality by saving default values. No further adjustments will be saved after theuser saves the scan; for example, adjustments made on an analysis screen will notbe saved.

• Auto/BC: Optimizes brightness and contrast settings of the fundus view.

Tip: You can switch between color and grayscale globally, for all viewports, byselecting or deselecting Colored OCT in the Tools menu (or by pressing F9 on thekeyboard). Colored OCT is the default.

• Image Adjustment Tools: When you scroll over the upper right-hand corner of theFundus Viewport or the Scan Display, the following image adjustment tools appear:

Note: Brightness/Contrast and Color adjustments apply simultaneously to all scanviewports. For example, if you select Brightness/Contrast for one viewport, the brightnessand/or contrast changes every time you click and drag your mouse over that viewport, untilyou select Normal.

Adjust Black Level: adjusts the lower limit of the intensity histogram,allowing you to adjust the contrast in the displayed image.

Auto Brightness/Contrast

Reset

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Note: Between the fundus image and its overlay, Brightness/Contrast and Color operateindependently. Right-click on one or the other to apply such changes. Some optionsfunction as a distinct display mode and that viewport or overlay remains in that mode untilyou click Reset, Normal or select another mode. Selecting Normal does not reset theviewport to its initial brightness and contrast settings. You must press Reset to return to theoriginal Brightness and Contrast settings.

Note: Additional right-click menu options are available when viewing saved images inAnalyze mode. See Image Display Options During Analysis on page 4-11 fordetails.

Fundus Image, Overlay and Scan Image Options

Note: Not all display options apply to every kind of image, and in these cases they are notavailable. For example, Movie does not apply to the fundus image or its overlay, sincethese are single images. For more information on the Movie option, go to page 4-12.

Review Screen for HD 5 Line Raster Scan

Figure 3-17 Review Screen for HD 5 Line Raster Scan

For the HD 5 Line Raster scan, the REVIEW SCREEN presents the frozen iris and fundusimages, along with all five lines of the scan. The exam protocol (ALL SCANS) appears at topleft, with the eye and name of the scan type below it. The upper left viewport shows thefrozen iris image, while the lower left shows the fundus image with a scan image overlaythat shows the placement of the 5 line scans with the currently selected line in blue. Thefive viewports on the right show each of the line scans from top to bottom. The center

Frozen Iris Image

Fundus Imagewith 5 Lines

Overlay

5 Line Scans–Selected Scan

Larger


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viewport (third line) is seen in larger view, by default. When you click any of the smallerscan images, it becomes the largest so you can view it in more detail.

• Signal Strength Indicator: This appears in the center near the top. It ranges from 0-10,with 10 being maximum signal strength. When values are less than 6, the indicatorcolor is red (below acceptable threshold); when 6 or higher, the color is green(acceptable).

Note: The Signal Strength indicator applies to the scan as a whole.


The applicable image display options are available—see Image Display OptionsDuring Review on page 3-24 for details.

Review Screen, HD 5 Line Raster

Initially after scan acquisition, unenhanced line scans are shown in the viewports. Theenhanced scans appear a few seconds later. The enhancement process can be stopped atany time in order to return to the acquisition screen by clicking on the Try Again button onthe Enhancing Image dialog box.

Review and Save or Try Again

The purpose of the REVIEW SCREEN is for you to evaluate the scan image quality, whereuponyou can either save the scan or delete it and try again:

• To save the scan, click Save (or press Enter on the keyboard). You will return to theACQUIRE SCREEN, where Cirrus marks the scan as complete with a checkmark on theleft, and puts a number on the right showing how many of that scan you have saved.

Or• Click Try Again (or press the Esc key on the keyboard) to delete the captured images

and return to the ACQUIRE SCREEN to capture another scan using the same scan type.• If you click Finish without saving first, a prompt will appear asking you if you want to

save before returning to the ACQUIRE SCREEN.

Criteria for Reviewing Good Quality Cirrus HD-OCT Scans

During scan review, use the following criteria to ensure that an image you have captured issuitable.

1. The fundus image:

• The focus should be sharp and clear, preferably with good visibility of thebranching blood vessels.

• The scan overlay should be centered on the fovea or optic nerve head.

• The fundus image should have uniform illumination without dark corners.

• There should be few, if any, artifacts that may cast shadows on the OCT scan.

Acquire Scans


3-28

• The OCT en-face image should have minimal saccades and no saccades throughthe area of interest (macula, for example).

2. The OCT scan image:

• OCT scan should be complete in all windows without missing data.

• Color density should be the same from end to end.

• Signal strength should be 6 or greater.

Repeating Scan Setup and Alignment

Cirrus HD-OCT contains automatic and manual functions to repeat scan setup andalignment during follow-up patient visits. Auto Repeat and Repeat Setup are available ifyou have saved the same scan type for a patient and eye on a previous visit. They repeat allthe relevant parameters from the previously acquired scan for the patient. The repeatedparameters include chinrest alignment, scan pattern and fixation target placement,Enhance (polarization) and Center (z-alignment) settings, focus, brightness, contrast andillumination settings.

Auto Repeat is a global setting available in the Tools menu. When enabled, the instrumentautomatically adjusts the ocular lens and chinrest to the previous settings for the samepatient, eye, and acquisition function. These adjustments occur with the patients chin in orout of the chinrest. It takes a few moments for the chinrest to move and all parameters tobe applied.

The Repeat Setup button is available to manually apply the repeat parameters ifthe Auto Repeat global option is not selected or not licensed. The button is enabled whena scan pattern for an eye that was previously saved for the patient is selected. Thefunctionality when the button is selected is the same as when Auto Repeat is enabled.

Auto Repeat and Repeat Setup should get you close to the correct alignment for thecurrent scan, although you still may have to make small adjustments. Both options alsoload the fundus image and scan pattern from the previous visit and display the previousfundus image and scan pattern statically within the fundus viewport.

You cannot use Auto Repeat or Repeat Setup to repeat a scan you have saved today, nor torepeat a scan type other than those currently selected. The Acquire Screen, HD 5 LineRaster on page 3-19 offers these options, enabling you to select any previous scan of anytype to repeat.

Repeat Scan Alignment Using Saved Scan Overlay

When you use Repeat Scan, the previously saved OCT fundus image of the scan you wishto repeat is overlaid in the scan pattern box on the live fundus image. This helps you toalign the previous scan to the one you are attempting to acquire. Click on the scan patternbox to drag it to the desired position. The Transparency slider activates when you arerepeating a scan, so you can adjust the transparency of the opaque overlay and view the

Tools menu


Acquire Scans 3-29

correspondence of the underlying live fundus image with the saved overlay. You may needto increase the overlay transparency to see the fixation target location.

Figure 3-18 Acquire Screen Displaying Overlay

The factory default setting for Auto Repeat is off. If you activate the Auto Repeat feature,the system will automatically position the chinrest and ocular lens according to theposition used in the previous visit for the given scan type selected. Depending upon thepatient's current position, adjustments may need to be done to obtain optimal focus of theLSO and OCT scan. When you switch to another scan type, the chinrest and ocular lensposition will move accordingly to align with the previous visit scan. This may require moreadjustments to obtain the correct patient position.

Auto Repeat can aid your workflow in the following situations:• You perform only one type of scan per visit.• You perform multiple scans and scan types but in different scan areas, for example

Macula Cube 512 x 128 followed by Optic Disc Cube 200x200.• The patient is able to maintain head position between scans.

Auto Repeat may not be desirable for use in the following situations:• You perform multiple scans using different scan types in the same scan area per visit,

for example: Macula Cube 512 x 128 followed by HD 5-line raster, or Macula Cube 512x 128 followed by Macula Cube 200 x 200. In this instance, using settings from thecurrent visit is more efficient.

• The patient has difficulty or is unpredictable in maintaining head position. In thisinstance, the repeat scan may be very different from the current position.

If you do not want the chinrest and ocular lens to move from the currently aligned positionwhen switching to another scan type, you have the following options:

Acquire Scans


3-30

• Leave the factory default setting of Auto Repeat off. The Repeat Setup button isavailable if you want to use previous scan settings for any scan you wish to acquire.

• Turn off Auto Repeat prior to scan acquisition by deselecting Auto Repeat in theTools Menu.

• Turn off Auto Repeat after the initial chinrest and focus adjustments are in place, orafter acquiring the first scan, and prior to choosing the second scan. This will ensurethat the settings used for the first scan will be maintained.

Click on the Capture button to save the image.

Repeat Scan Function

When you reach the ACQUIRE SCREEN for any patient with previous scans in the Cirrusdatabase, the Repeat Scan... option becomes available in the Tools menu. Click Tools >Repeat Scan... or press F6 on the keyboard to open the Repeat Scan dialog, where you canselect a scan to repeat.

Figure 3-19 Repeat Scan dialog

The REPEAT SCAN dialog lists all previous scans for this patient by exam date and eye andshows the fundus image for the scan you select. This option allows you to select a scantaken on the same day. This is especially useful when a scan had been taken away from thecentral fixation area or if a patient had been scanned previously with a Macular Cube200x200 scan but now will be scanned using the Macular Cube 512x128 scan. Theprevious Macular Cube 200x200 scan can be used as reference in this manner whereas itcould not be referenced via the Repeat Setup button.

Click OK to return to the ACQUIRE SCREEN and apply the parameters of the scan you selectedto repeat. It takes a few moments for the chinrest to move and all parameters to beapplied. You can use the repeated parameters as a starting point for further adjustmentsyou may wish to make.


Analyze Scans: Macula 4-1

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Chapter Overview

This chapter explains how to use the macula analysis portion of Cirrus HD-OCT software.Topics covered in this chapter include:

• Access Analysis, page 4-1• Macular Thickness Analysis, page 4-3• Macular Change Analysis, 4-13• Advanced Visualization, 4-19• Advanced RPE Analysis, page 4-24• HD 5 Line Raster Analysis, page 4-31• High Definition Image Analysis – 5 Line Raster, page 4-32• Ganglion Cell OU Analysis, page 4-33• Reports and Printing, page 4-37

Note: See Appendix D for information on the RNFL Normative Database. See Appendix Ffor information on the Ganglion Cell Normative Database.

Access Analysis

To access analysis, click the Analyze button when it is active; it is active when a patientrecord with saved exams is selected or is open. Usually you will access it after selecting apatient from the ID PATIENT SCREEN. When you click the Analyze button, the ANALYZE SCREEN

appears (see Figure 4-11 on page 4-18). Initially it shows four columns near the top,which list:

• the patient’s exams by date (left column), with the most recent exam date selected bydefault;

• for the selected exam, the right eye OD scans (center left column) and left eye OSscans (center right column) by scan type;

• the column on the right where you can select among available analyses for theselected scan type, after you select a scan.

The image display portion of the screen is blank until you select a scan from the OD or OScolumn and then select the desired analysis. Click to select any scan from the OD or OS list,and click the corresponding analysis at the right. The images will appear in the imagescreen below, after a few seconds.

The ANALYZE SCREEN enables you to view and measure anatomical structures depicted in thescan images. Cirrus HD-OCT provides the following analyses for the macula:

• Macular Thickness Analysis for cube scans, page 4-3• Advanced RPE Analysis for cube scans, page 4-24• High Definition Image Analysis – 5 Line Raster, page 4-32• Ganglion Cell OU Analysis, page 4-33

Analyze Scans: Macula


4-2

Analyze Screen Common Functionality

The following information applies to the ANALYZE SCREEN in general, independent of thetype of scan you are viewing.

• Delete Scan button: Click the Delete Scan button to delete the currentlyselected scan. A dialog will prompt you to confirm your choice, as shown on the left. Ifa scan is not archived to DICOM Archive, you can delete the scan from the scan list, ordelete it after the analysis is loaded. This button is disabled if the scan is alreadyarchived.

• Print button: Click Print to initiate printing. You can print to paper, create aPDF, or export a number of image types, including PDF, TIFF, and JPEG to name a few.See Reports and Printing on page 4-37 for details.

• Save Analysis button: Click Save Analysis to save the current analysis with thechanges currently applied. The next time you open this analysis on the same scan, thesaved analysis will appear initially. You can discard saved changes at any time andreturn to the original analysis by using the Discard Changes button.

• Discard Changes button: Click Discard Changes to reload the originalanalysis, discarding all changes previously saved.




right of scan display.• For diagonal scans in 5 Line Raster, left takes precedence over bottom, so that left of

scan equals left of scan display and right of scan equals right of scan display.

Retinal Layers Automatically Detected and Displayed

• Cube scan analyses incorporate an algorithm to automatically find and display theinner limiting membrane (ILM) and the retinal pigment epithelium (RPE).

In the scan images, which are cross-sections (slices), the layers appear as coloredlines that trace the anatomical feature on which they are based. The ILM is repre-sented by a white line, the RPE by a black line. These lines are also known as segmen-tation lines. These layers serve as the basis for the macular thickness and volumemeasurements in the Macular Thickness Analysis (page 4-3). In the MacularThickness Analysis, the ILM and RPE layers are presented in their entirety asthree-dimensional surface maps.

• Show/Hide Layers button: Click Layers to hide or show the colored linesindicating the ILM and RPE layers


For horizontal scans, left equals leftand right equals right. For verticalscans, left to right equals bottom totop. For diagonal scans, left takesprecedence over bottom.



Macular Thickness Analysis

The Macular Thickness Analysis (MTA) provides interactive scan images as well as thefundus image with scan cube overlay. To see this analysis after selecting a cube scan, selectMacular Thickness from the list on the right. The default screen, shown in displays:

• the identified fovea location.• the fundus image with scanned cube overlay or colored thickness map. • the ETDRS grid map with normative data.• a table containing average thickness and volume measurements.• a colored 3-D thickness map.• 3-D surface maps of the ILM and RPE.

You may also manipulate the fovea location on this screen, which will update the datatable and the ETDRS grid thickness measurements.

Figure 4-1 The Analyze Screen for Macular Thickness

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1 Exam (date), OD and OS scan lists for selected exam, analysis list 7 Slice through cube side

2 Slice through cube front 8 OCT fundus image

3 ILM to RPE Thickness Map 9 Average thickness and volume measurements

4 3-D Surface Maps 10 Normative Data Details

5 Anterior Layer (ILM) 11 Fundus image with scan cube overlay

6 Posterior Layer (RPE) 12 Color code for thickness overlays



4-4

3-D Surface Maps

Interactive three-dimensional (3-D) surface maps appear down the right side. The top mapdisplays the thickness between the ILM and RPE as a color coded three-dimensionalsurface. The middle map shows the upper (anterior) of the two layers, the ILM. The lowermap shows the lower (posterior) of the two layers, the RPE.

• The surface maps are fully interactive. Click and drag to rotate a map in any directionand thereby view it from any perspective. The maps include the same slice navigatorsyou are accustomed to seeing on the scan images and fundus overlay. As usual, youcan click and drag each line to change the currently selected slices and thecorresponding scan image updates immediately. You can double-click a map to view itin full screen (or right-click and select Full screen). As in normal view, you can rotatefull screen maps in three dimensions.

Figure 4-2 Same full screen 3-D surface map, showing rotated views

• Right-click display options for 3-D surface maps. Right-click on a 3-D surface mapto access the display options at left, which function as in other contexts. See onpage 4-11 for details.

ILM = inner limiting membraneRPE = retinal pigment epithelium

from underneath, front

initial

rotated clockwise and fronttipped down

tipped backward

rotated counterclockwise andfront tipped up slightly



Fundus Image Overlay Options

By default, the fundus image overlay displays ILM - RPE, where you view on the fundusimage a corresponding (in terms of color) thickness representation from above (en face) asappears on the contoured thickness map to the right. The drop-down menu below thefundus image gives you the following options: None, ILM - RPE, OCT Fundus, and ETDRSPosition. Use the Transparency slider below the drop-down menu to adjust thetransparency of the overlay.

Numerical Average Thickness and Volume Measurements

The area at lower left presents average thickness and volume numerically.

Figure 4-3 Numerical average thickness and volume information

It includes a table with central subfield thickness for the central circle of the circular mapknown as the ETDRS Grid, and total volume and overall average thickness for theILM - RPE tissue layer over the entire 6 x 6 mm square scanned area. The ETDRS Gridshows overall average thickness in nine sectors. This circular map is composed of threeconcentric circles with diameters of 1 mm, 3 mm and 6 mm, and except for the centralcircle, is divided into superior, nasal, inferior and temporal quadrants. The central circle hasa radius of 500 micrometers (1 mm diameter). The OCT fundus image to the right showsthe surface of the area over which the individual thickness measurements were made thatcontribute to the subfield averages.

FoveaFinderTM: Automatic Fovea Identification

This feature is active in the Macular Thickness Analysis and the Macular Change Analysis.Cirrus identifies the fovea location automatically by looking for the reduced reflectivitybelow the retina. When the analysis screen first comes up, the fovea location has beendetermined and is indicated by the overlay position, the position of the slice navigators inthe cube, and on the 3-D surface maps. The ETDRS grid in Figure 4-3, shows the values,in micrometers (μm), of the ILM-RPE thickness, calculated as described above. You canchange the position of the ETDRS grid. If you change it, the reported values also change.

En Face Explained


ETDRSGrid



4-6

The position of the fovea and the center of the ETDRS grid is shown below the grid. In theexample above, the fovea is located at the intersection of slice 253 and 64.

If Cirrus cannot identify a fovea in the scan, it reports: “Fovea not found.” In this case, thecenter of the scan is used for the initial placement (position 256 and 64 for 512x128 scansand position 100 and 100 for 200x200 scans). It is also possible for the algorithm to find adepression in the reflectivity around the ILM that is not related to the fovea – in this case,the reported fovea will be wrong. In both of these cases, the user can set the foveamanually using the buttons described below. The most common pathologic conditions thatcause failure of the fovea-finding algorithm are those that cause the greatest disturbanceof the foveal architecture, such as AMD, other causes of macular edema, and proliferativediabetic retinopathy. Epiretinal membranes and other vitreoretinal interface disorderswhere the vitreoretinal interface becomes distorted can also cause the algorithm to fail.

If the fovea is very far from the center, the algorithm may fail to find it. In order to ensurethat the fovea is within a reasonable distance of the center, it helps to use the alignmenttool during acquisition (see Place Scan Using Fundus Viewport, on page 3-14 andOptions and Reset buttons on page 3-15). It also helps for subsequent visits to usethe Repeat Setup and Repeat Scan Alignment feature (see Acquire Screen, HD 5 LineRaster on page 3-19 and Repeating Scan Setup and Alignment on page 3-28).

Working with Scan Cube Overlays

In the ILM-RPE overlay, the colors on the overlay correspond to the color-coded side barscale on the right. The colors denote retinal thickness in micrometers (μm).

When ETDRS Position is selected from the overlay menu, a small red circle appearscentered around the Cirrus-calculated fovea position. This calculated ETDRS Grid positioncan be repositioned by clicking and dragging the circle using the mouse.



The thickness grid also moves in conjunction with the repositioning of the ETDRS Gridposition on the overlay, as shown in Figure 4-4.

Figure 4-4 Thickness Grid Movement

Interactive function buttons for ETDRS include:• Snap slice navigators to ETDRS Grid center position: Moves the slice navigators

to the ETDRS Grid center position. • Reset ETDRS Grid: Moves the ETDRS Grid back to the Cirrus-calculated fovea

center location. • Set ETDRS Grid center to slice navigator position: Moves the ETDRS Grid center to

the center defined by the slice navigators position.• Snap to Center: Moves slice navigators to the center of the 6x6 mm square.

These tools can be used to establish a new ETDRS Grid position after adjusting the positionwith the slice navigator in any of the various screen options. Also, as you adjust the ETDRSGrid position, the thickness grid also reflects the new values associated with the newsetting. To save the new fovea position for future analysis, click on the Save button inthe upper right-hand corner of the screen.

This interactive analysis screen gives you several options to view patient data. For example,when you move one of the slice navigator bars and then select , the thickness gridreflects that change as the grid moves and the values change. Select to move theETDRS Grid back to its original location. Select to move the slice navigators to theETDRS Grid center.

Use the button tools to line up the slice navigators with ETDRS Grid position and vice versa.For example, manually drag the ETDRS Grid to a new position on the overlay, then:

• Select to center the slice navigators over the new ETDRS Grid position, as shownon the left. Note that the thickness grid does not change location.

ETDRS Gridpositionmoved

Thickness grid movesin conjunction with ETDRSGrid



4-8

• Select to reset the ETDRS Grid position to the original Cirrus-calculated position.The slice navigators also move back to their original positions over the ETDRS Gridposition.

Now move the slice navigators to a new position, as shown in Figure 4-5. The ETDRSGrid position does not change, nor does the thickness grid position.

Figure 4-5 No Movement of Thickness Grid

• Select to align the ETDRS Grid position with the slice navigators.• Select to move the ETDRS Grid and the slice navigators back to their original

location.

Macula Normative Database

The Macular Thickness Analysis supports the clinician in identifying areas of the maculathat may be of clinical concern by comparing the measured macular thickness toage-matched data in the Cirrus Macula Normative Database1. Normative data that isage-matched to the patient appears when you perform a Macular Thickness analysis onpatients at least 18 years old. Data was not collected from subjects less than 18 years old.

The Normative Database uses a color code, as seen in the legend at left, to indicate thenormal distribution percentiles. The color code applies to the ETDRS grid average thicknessvalues and the data table (see Figure 4-5 above).

Among same-age individuals in the normal population, the percentiles apply to eachparticular retinal thickness measurement as follows:

• The thickest 1% of measurements fall in the light red area. Measurements in light redare considered outside normal limits. (light red > 99%, above normal limits).

1. The Macula Normative Database is an optional feature that may not be available in all markets, and when available in a market,

may not be activated on all instruments. If you do not have this feature and want to purchase it, contact Carl Zeiss Meditec. In the

U.S.A., call 1-877-486-7473; outside the U.S.A., contact your local Carl Zeiss Meditec affiliate or distributor.



• The thickest 5% of measurements fall in the light yellow area or above (95% < lightyellow 99%, suspect above normal)

• 90% of measurements fall in the green area (5% green 95%).• The thinnest 5% of measurements fall in the yellow area or below (1% yellow <

5%, suspect below normal).• The thinnest 1% of measurements fall in the red area. Measurements in red are

considered below normal limits (red < 1%, below normal limits).

Note: Clinicians must exercise judgment in the interpretation of the macula normativedata. For any particular measurement, note that 2 out of 20 normal eyes (10%) will falleither above or below green. Interpretation of the 1st Percentile: Values color-coded as “1st percentile” are lower than99% of the database sample, but may not extrapolate well to the general population withless than 300 subjects in the reference database. Results falling in this region should beinterpreted with caution.Interpretation of the 5th Percentile: Values color-coded as “5th percentile” are lower than95% of the database sample. The 95% Confidence Interval on the 5th Percentile extendsfrom the 2.5th percentile to the 7.7th percentile of the normative database.Information icons displayed on the Analysis screen offer additional information aboutthe normative database limits. Hovering over the icon will display a tooltip, and clickingthe icon will create a printout of the additional information presented. See NormativeData Details Report on page 4-41 for more information.

Additional Features in Macular Thickness Analysis

The buttons above appear from left to right in the Macular Thickness analysis. If you mouseover the buttons, their function appears in the form of a tool tip. The following paragraphsdescribe the additional features available on the Macular Thickness analysis screen:

High-Res Images button: A pair of high-definition scans are taken at thebeginning of each Macular Cube 512x128 and Macular Cube 200x200 scan. Selectthis button to display these central X and Y slices in high resolution. These two slicesare composed of 1000 A-scans (for Macular Cube 200x200) or 1024 A-scans (forMacular Cube 512x128). The system provides this feature to enhance resolution in thecentral area of the scan, which corresponds to the center of the fixation target. TheEDTRS Grid will not change position when the High-Res Images button is selected.These high-definition images may be enlarged to a full-screen view.

The slice navigators will be set to slice 256 and 64 with the Macular Cube 512x128 orwill be set to slice 100 and 100 with the Macular Cube 200x200 scan. To return to thestandard resolution scans, re-select the High-Res Images button or move either the Xor Y slice navigator to a different position.

Edit Layers1 button: Click Edit Layers to open the EDIT SEGMENTATION screen, asshown in the following figure. Here you can edit the currently selected X and Y slice



4-10

placement on the ILM and RPE layers; Cirrus calculates thickness between these lay-ers.

Figure 4-6 Edit Segmentation Dialog

This feature is especially useful in cases where the retina has structural anomalies orpathology that may cause the algorithms to incorrectly trace the actual boundaries.Click and drag the ILM line or the RPE line, shaping and placing it in the desired loca-tion by your mouse movement. You can draw and redraw the line or any portion of itrepeatedly, selecting any point on a line to start each successive drawing action.

Note that when you mouse over a line, it “pops,” or becomes thicker. The boundarylines you trace will never break. However, they will not cross each other.

The buttons (shown at left) enable you to copy changes from one slice to the nextslice or to the prior slice

Buttons 1 and 4 allow you to move through the layers. Button 2 copies your changesto the prior slice, and button 3 copies your changes to the next slice.

Your changes are not saved as part of the Macular Thickness analysis until you clickthe Save button, , on the ANALYZE SCREEN. Then they will persist with the analysisuntil you re-edit the same layers and click Save again, or click Discard Changes,

, when viewing the edited analysis. The segmentation changes affect only thespecific X and Y slices you edit, but do take immediate effect in the 3D surface mapsand all other ILM to RPE thickness measurements.

Ruler button: Click Ruler and then click and drag in a scan image or the fun-dus image to draw a straight line that measures distance between the start and stoppoints. The resulting measurement appears next to the line in micrometers.

• You can select and adjust the lines you draw: click and drag an endpoint to adjustits placement (and the line length), or click and drag the middle of the line tomove it as a whole.

• Click Ruler again to create additional measurement lines.

1. Edit Layers is an optional feature that may not be available in all markets, and when available in a market, may not be activated

on all instruments. If you do not have this feature and want to purchase it, contact Carl Zeiss Meditec. In the U.S.A., call

1-877-486-7473; outside the U.S.A., contact your local Carl Zeiss Meditec affiliate or distributor.

1 2 3 4



• These measurements are saved when you close the analysis. The changes willappear on the Macular Thickness Analysis printout, but not in the Advanced RPEAnalysis.

Note: You may use the ruler tools with the high definition images.

Delete Measurements button: Click Delete to delete the currently selectedmeasurement lines. You can select lines in more than one image at a time. To deselecta line, click anywhere on the same image but off the line.

Image Display Options During Analysis

Right-click on the fundus image, on its overlay, or on a scan image to access the imagedisplay options seen in the menu at left, or a subset of them. A checkmark indicates whenan option is selected. (Right-click menu options are not available for 3D volumerenderings.)

• Normal: Selected initially, clicking Normal exits other display-change modes, andthereby fixes or freezes the changes you have made to that point.

• Reset: Resets the current display to default settings.• Zoom: Gives access to the following options:

• Unzoom: Unzooms the image.

• Rectangle: When selected, click and drag toselect a rectangular area to fill the screen.

• Continuous: When selected, click and drag up to increase the zoom; click anddrag down to decrease the zoom.

• Pan: This option is present only when the image is zoomed. When selected, click anddrag the image to view other parts of it.

• Full screen: Select to view the image in full screen.

✐ Tip: You can also double-click most images to open them in full screen.Double-click a full-screen image to return to normal view or click the Backbutton.

• Save image as...: Saves the current image on screen in the location you select. See theExporting/Saving to the Hard Drive below (page 4-12).

• Tag for print: Tags the current image for inclusion in a custom report printout. Thisoption is available only for Advanced Visualization. See Custom Print on page 4-54for details.

• Movie: Changes the display to movie mode—movie controls will appear—so you canview all slices in the current plane in succession as a movie. This option is available



4-12

only for OCT viewports. Movie is only available for Macular Thickness and AdvancedVisualization analyses.

Figure 4-7 Movie Controls

• Hide Slice Navigator: Hides the slice navigator, including the colored outline aroundthe image.

• Brightness/Contrast: When this feature is used, values appear on theimage that reflect the numerical parameter values you select. Left-click the mouse andhold while moving the mouse up and down changes the brightness; moving themouse left or right changes contrast. They also work in combination when you movethe mouse diagonally. To retain the settings for this session, right-click the image tobring up the menu, then select Normal.

• Color: Selected by default; deselect to view in grayscale.

✐ Tip: You can switch between color and grayscale globally, for all viewports,by selecting or deselecting Colored OCT in the Tools menu (or by pressingF9 on the keyboard). Colored OCT is the default.

• Save movie as...: Opens the Save As dialog so you can save the movie of the currentplane in video format. This option is available only for OCT viewports.

Note: When using the Zoom or Brightness/Contrast feature on the ONH and RNFL OU orRNFL Thickness analysis screens (Chapter 5), do not click and drag the mouse inside thecircle on the fundus image; instead of expected results, this will cause the circle to move toa different location on the image.

Exporting/Saving to the Hard Drive

Note: Do not export or save data—including images and movies—to the C: drive of aCirrus instrument, which includes the desktop. The Cirrus hard drive is partitioned into C:and either a D: or an E: drive, and the C: drive is reserved for operating system and Cirrusapplication files. The C: drive is relatively small and can be filled up quickly, which rendersthe system unusable. The D: (or E:) drive is reserved for data and therefore is relativelylarge. If you want to export or save data to the Cirrus hard drive, either locally or to aconnected Cirrus system on the network, select (a location in) the D: (or E:) drive as thetarget.



Macular Change Analysis

Selecting the Macular Change Analysis1 (MCA) option allows you to compare two MacularCube 512x128 scans or two Macular Cube 200x200 scans side by side, as shown in Figure4-8. The default is to compare the two most recent scan dates. The Cirrus automaticallyregisters the en face images from the two dates so that the images you see aresynchronized to show the equivalent location of the retina in each image. In addition, thecolor-coded thickness maps for the two images, as well as the thickness difference map,are displayed.

When automatic registration occurs, the current image (which appears on the right-handside) is aligned to the prior image (which appears on the left-hand side). Both the en faceimage and the fundus image are compensated for the differences in scan locations duringacquisition. The registration process maps similar anatomical structures, such as bloodvessels, to each other to obtain the proper registration. Rotation of an image due to thepatient’s eye being rotated from one session to another is also accounted for in theregistration.

Areas of the current image that do not overlap with the prior image are not included in thefinal registered image. This causes the thickness map on the right side and the fundusimage to display a black border around the outside edge(s) of each view. The size of theborder depends on how much the current image was shifted to align with the prior image.In addition, the right-hand B-scan will show an incomplete view in the areas where datawas not acquired in both scans.

The ETDRS Grid position circle is automatically positioned over the fundus image of theolder scan data. You can adjust this position by clicking anywhere within the OCT scanboundary, and dragging the ETDRS Grid to a new position. Thickness values areautomatically recalculated corresponding to the new ETDRS Grid position.

The Thickness Difference Map is seen at the far right of the display. It displays the thicknessdifferences between the two scan dates (current thickness minus prior thickness, inmicrometers) at each pixel location. The difference map has a different color scale torepresent the thickness change. This color map is indicated to the right. Warmer colorsindicate an increase in the thickness; cooler colors indicate a decrease in thickness. Thetransparency slider beneath each overlay can be adjusted, as required, to enhance theimage.

1. Macular Change Analysis is an optional feature that may not be available in all markets, and when available in a market, may not

be activated on all instruments. If you do not have this feature and want to purchase it, contact Carl Zeiss Meditec. In the U.S.A.,

call 1-877-486-7473; outside the U.S.A., contact your local Carl Zeiss Meditec affiliate or distributor.



4-14

Figure 4-8 Macular Change Analysis screen

ETDRS Grid Location

Default ETDRS Grid center

When you enter Macula Change Analysis, Cirrus loads the saved fovea for each exam. Thisfovea location is determined by the last saved fovea location for that exam. Typically, thiswill be the fovea that Cirrus found automatically. However, if you or another user changethe fovea location for the exam in the Macula Thickness Analysis, and save the analysisresult, then that is the fovea used in Macula Change Analysis.

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1 Sync Lock

2 Foveal Target

3 Thickness Map

4 ETDRS Grid boundary (black circle)

5 OCT scan boundary (yellow square)

6 Thickness Difference Map

7 Thickness Map

8 Slider Navigator



1. When automatic registration is successful, or when manual registration is applied, theinitial location of the ETDRS Grid center for both loaded scans is determined by thelocation of the fovea in the prior (left-hand) image. This is because successfulregistration implies that each pixel in the current image maps directly to the samepixel in the prior image. Thus, the foveas do not need to be independently identified.

2. When No Registration is applied, the initial location of the ETDRS grid center for bothscans is taken from the saved value for that scan.

Synchronized Data Review

When the images are synchronized, the analysis allows the user to manipulate the data onone exam image, while the identical movements are tracked on the second exam for a sideby side comparison.

When the sync lock is selected, , you can adjust the slice navigator or image sliderbar to simultaneously move through the images and view the data. If the sync is notlocked, , adjustments to one overlay do not effect the other.

Adjusting the ETDRS Grid centers

You can adjust the position of the ETDRS Grid center. If Sync lock is on, you can make theadjustment on either image, and it will be applied to the other image. If Sync lock is off,you must adjust each center individually.

Registration Successful

The Registration Succeeded message along with the green flag indicate that the twochosen images did register reliably. A red flag appears if the registration fails. This could becaused by weak signal strength, poor alignment, opacities, large differences in the scanareas or larger differences in retinal anatomy. When that occurs, you may attempt to useManual registration by selecting from the Registration dialog box or, if available, selectanother image for comparison. In the Registration dialog box, you may also choose NoRegistration.

Note: The indication for success or failure of the registration algorithm is based on across-correlation metric computed from the two images after registration. A threshold isused on this metric to make a binary decision of success or failure.



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Registration Review

Registration between the two fundus images may be compared by selecting theRegistration Review button: . The results are displayed on a pop-up screen, as shownin Figure 4-9.

Figure 4-9 Registration between Fundus Images

In this screen, image 1 is the original image. Image 2 is the en face image from the mostrecent visit that has been registered to Image 1. The bottom image is an overlay of the twoexams. The image slider allows you to adjust the view of the overlaid images: slide to theleft to view image 1, to the right for image 2. Black borders might be seen in Image 2. Thisis the area of the second image that does not correspond to the first image when the twoimages were registered to each other.

To manually adjust the registration, select the Manual Registration button. Select three tofive corresponding points on Image 1 and Image 2 by using the mouse click. See Figure4-10. Place each point over an identifiable feature that appears in both scans that youexpect to be constant across scans. For example, a blood vessel bifurcation or a bend in ablood vessel can be used.

Figure 4-10 Manual Registration

Undo buttons



Select Review Registration to view your manually adjusted overlay. Use the slider above theoverlay, as needed, to change the transparency to see more of Image 1 or Image 2. Bymoving the slider back and forth, you can see if blood vessels or other features from oneimage align with the identical features in the other image. To return the registration to theoriginal setting, press the Reset Overlay button. If you are not satisfied with the positioningof the points, click on the Undo button, , to delete all points and then make new pointselections.

Darker areas on the lower registration screen occur where there is no data to compare. Thiswill occur when the data points selected create an offset of the images. To see the finalregistered image, move the slider all the way to the right. This black border will also beseen on the thickness map and the thickness difference map on the MCA screen. Whenyou are satisfied with the resulting overlay, select OK. To reset the values to the originalregistration, click Cancel.

The XML export from the MACULAR CHANGE ANALYSIS screen is performed by clicking on theXML Export button (shown on the left). For further details on XML export, see XML Exportin Chapter 9.



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Macular Change Analysis – Manual Selection

When there are two or more scans taken on the same day, the most recent scan (the onewith the latest time stamp) is chosen as the default scan to be used in Macular ChangeAnalysis. Sometimes, this scan is not the best to use for comparison. The scan may nothave the best signal strength or the scan was taken in a position away from the center and,therefore, would not be a good match. You are able to manually choose a different scanusing the manual selection process.

1. At the top of the Analysis screen, select the scan date and the scan you wish to use asthe more current scan (the scan information that will appear on the right side of thescreen).

2. Select Macular Change Analysis – Manual Selection from the far right column.3. A list of eligible scans will appear in a dialog box (see Figure 4-11).4. Click on the scan you wish to include in the MCA. A green check mark will appear next

to the scan.5. Click on Next to proceed. The window will collapse and the scan you chose will

appear as the scan on the left-hand side of the MCA screen.

Note: You may not choose two scans from different visits from the manual selectionwindow. You may only select one scan in this way to use as the earlier of the two scans.

Figure 4-11 Macular Change Analysis–Manual Selection screen



Advanced Visualization

Figure 4-12 Advanced Visualization Analyze Screen

The ANALYZE SCREEN for Advanced Visualization, Figure 4-12, presents an interactivemulti-planar reformat (MPR), which enables you to view image cross-sections throughthree dimensions. The example above is for a Macular Cube 200x200. The upper leftviewport shows the saved fundus image with an optional en face scan overlay. The otherthree viewports show cross-sectional scan images in three planes. Thinking of the data as acube, the viewports show the data in planes parallel to the side of the cube (Y plane, lowerleft viewport), the front of the cube (X plane, upper right viewport) and the top of the cube(Z plane, lower right viewport), as shown in Figure 4-12 and to the left. Multi-PlanarReformat (MPR)

• The viewports are interactive: Click and drag the triangles or click on a scan viewportand use the mouse scroll wheel to “move through” the active plane of the viewport;you will see the resulting cross-sections update simultaneously in the other viewports.This functionality enables you to quickly search through the data cube and stop whenyou see an area of interest.

1

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1 Exam (date), OD and OS scan lists for selected exam, analysis list

2 X slice through cube front

3 Z slice or slab through cube top

4 Y slice through cube side

5 Fundus image with scan cube overlay

Front of cube =fast B-scan planeblue scan line

Data Cube Orientation

upper right viewport

slow B-scan planemagenta scan line

Side of cube =

lower left viewport

Top of cube =en face scan planeyellow scan linelower right viewportX

Y

Z

En Face Explained




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Retinal Layers Automatically Detected and Displayed

• Cube scan analyses incorporate an algorithm to automatically find and display theinner limiting membrane (ILM) and the retinal pigment epithelium (RPE). Cirrus alsocalculates and presents a layer called RPEfit, which is a representation of a normalparabolic RPE for this eye, based on the retina’s overall curvature. You can use theRPEfit line to view variations from normal in the actual RPE contour.

In the scan images, which are cross-sections (slices), the layers appear as coloredlines that trace the anatomical feature on which they are based. The ILM is repre-sented by a white line, the RPE by a black line, and the RPEFit line is magenta incolor. These lines are also known as segmentation lines. You can customize the colorsused to display each of these lines, as explained below. These layers serve as the basisfor the macular thickness and volume measurements in the Macular ThicknessAnalysis (page 4-3). In the Macular Thickness Analysis, the ILM and RPE layersare presented in their entirety as three-dimensional surface maps.

Fundus Image Overlay Options

• Use the Overlay drop-down menu to select which overlay to use on the fundus image:None (default), Slice, OCT Fundus, Slab, ILM - RPE, ILM - RPEfit or RPE - RPEfit. Theslice and slab options correspond to the en face image in the lower right viewport.(The options ILM, RPE and RPEfit are variations of the slab. See Slice and SlabOptions on page 4-21 page for a description.) You can adjust the associatedTransparency slider from 0% (opaque) to 100% (fully transparent). The OCT Fundusoption is the same overlay (en face) shown on the fundus image in the REVIEW SCREEN.




Slice and Slab Options

The lower right viewport, Figure 4-13, has a drop-down menu to select Slice(default), Slab, ILM, RPE or RPEfit.

Figure 4-13 Analyze Screen showing a slab

When you select Slab, the other two scan viewports show two same-color dashedlines separated by a small distance. This separation is the slab thickness, which youcan adjust in either of the other viewports by dragging the posterior line by its handleon the edge. Dragging the anterior line handle moves both lines of the slab togetherto reposition it in the scan image. The resulting slab image you see represents anaverage signal intensity value for each A-scan location through the selected depth ofthe slab.

• The drop-down options ILM, RPE and RPEfit are variations of the slab. When youselect any of these, you view the slab (of selected thickness—you can adjust it asabove) relative to the selected layer. For example, if you select ILM (Figure 4-13),a dashed line of the same color as the ILM appears posterior to it, and theresulting scan image appears in the lower right viewport (and in the scan cubeoverlay when Slab is selected there). You cannot raise the lower dashed line abovethe upper one, and the minimum separation is 2 micrometers.




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Function Buttons in Advanced Visualization

The buttons shown on the left appear from left to right in the Advanced Visualizationanalysis, above the scan images at right. If you mouse over them, their function appears inthe form of a tool tip.

• Ruler button: Click Ruler and then click and drag in a scan image or thefundus image to draw a straight line that measures distance between the start andstop points. The resulting measurement appears next to the line in micrometers.

• You can select and adjust the lines you draw: click and drag an endpoint to adjustits placement (and the line length), or click and drag the middle of the line tomove it as a whole.

• Click Ruler again to create additional measurement lines.

• These measurements are saved after you close the analysis and will appear onreports (printouts) you make while they are present.

• Delete Measurements button: Click Delete to delete the currently selectedmeasurement lines. You can select lines in more than one image at a time. Todeselect a line, click anywhere on the same image but off the line.

• Show/Hide Layers button: Click Layers to hide or show the colored linesindicating the layers (ILM, RPE and RPEfit).

• Configure Layers button: Click Configure Layers to open the Layer ConfigurationDialog, Figure 4-14, where you can select the colors of the layers for ILM, RPE andRPEfit, and whether to display them or not.

Figure 4-14 Layer Configuration Dialog and Color picker

• Click a Color button for ILM, RPE or RPE-fit to open a standard color picker, whereyou can select a new color for that layer, or even define a custom color.

• The layers with their Display checkbox selected appear in scan images forAdvanced Visualization and Macular Thickness analyses for the scan you areviewing. Click to select or clear Display checkboxes as desired.



Note: Switching to a different scan or leaving the Analysis screen causes the selectedsegmentation colors to default to the original colors.

• Center button: Click Center to return the current slices to their default centralpositions.

• Tagged Images button: Click the Tagged Images button to view and adjustwhich images are tagged for custom printing. This button is active when one or moreimages have been tagged for printing by selecting Tag for print from the right-clickmenu. (See Custom Print on page 4-54 for details.)

The Advanced Visualization screen also uses the image display options available by usingthe right mouse click. See Image Display Options During Analysis on page 4-11.

Note: Brightness/Contrast and Color adjustments apply simultaneously to all X, Y and Zslices on screen (in OCT viewports or as the fundus overlay). If two Z slabs are on screen,one as the fundus overlay and one in the lower right viewport, Brightness/Contrast andColor adjustments made on either slab will apply to both. Between the fundus image andits overlay, Brightness/Contrast and Color operate independently. Right-click on one or theother to apply such changes. Some image display options function as a distinct displaymode and that viewport or overlay remains in that mode until you click Reset, Normal orselect another mode.

• For example, if you select Brightness/Contrast for one viewport, the brightness and/orcontrast changes every time you click and drag your mouse over that viewport, untilyou select Normal or Reset. Note that selecting Normal would not reset the viewportto its initial brightness and contrast settings.

Fundus Image, Overlay and Scan Image Options

Note: Not all display options apply to every kind of image, and in these cases they are notavailable. For example, Movie does not apply to the fundus image or its overlay, sincethese are single images. For the fundus overlay, the Brightness/Contrast and Color optionsare available only for Slice and Slab, not for OCT Fundus nor for the calculated thicknessoverlays (e.g., ILM-RPE). Another example is that Tag for print is available only in theAdvanced Visualization analysis.



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Advanced RPE Analysis

The Advanced RPE Analysis allows you to examine the status of the RPE in more detail thanthe Macular Thickness Analysis. In particular, Cirrus provides two algorithms, one toidentify and measure elevations in the RPE, and one to identify and measure areas ofsub-RPE illumination where the OCT beam is able to penetrate through to the choroid,indicating that the RPE is atrophic. Maps based on each analysis, as well as a map thatintegrates both analyses are presented to visualize these disturbances in the RPE, andnumerical results are provided to summarize them.

Within the Advanced RPE Analysis, there are two screens available for reviewing theresults. The first screen shows both the RPE elevation and the sub-RPE illumination resultsseparately as en face images. The second screen shows the integrated analysis along withcalculated values.

The RPE Advanced Analysis can be performed on both the Macula 512x128 and Macula200x200 scan data.

Performing an Advanced RPE Analysis

To perform an analysis:

1. Select the scan you want to analyze.2. Select Advanced RPE Analysis. For comparison, the best scan of the same type from

the most recent prior visit is selected by default. If you want to select a different scanfor comparison, select Advanced RPE Analysis - Manual Selection. If there is only datafrom one visit, the prior area will be blank on the Advanced RPE Analysis and thereport.



Advanced RPE Analysis Screen 1

Figure 4-15 Advanced RPE Analysis - Screen 1

RPE Elevation Map

The analysis displays an RPE Elevation Map as an overlay on the fundus image. Thetransparency is preset, however you can adjust transparency on the analysis screen usingthe control to the side (3 in Figure 4-15).

The pseudo-color aids in identifying bumps and discontinuities in the RPE. The map showscircles corresponding to 3 mm and 5 mm in diameter centered on the fovea. On the side ofthe map the legend shows how the colors correspond to the height of the elevations.

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1 RPE Elevation Map overlaid on fundus image

2 Circles on the RPE Elevation Map centered on the fovea location

3 Transparency adjustment for RPE Elevation Map

4 Line from fovea connecting closest sub-RPE illumination area

5 Transparency control for Sub-RPE Slab overlaid on OCT Fundus image

6 Sub-RPE Slab with overlaid segmentation of Sub-RPE Illumination

7 Horizontal tomogram showing RPE Elevation segmentation line

8 Fovea location for exam shown above



4-26

Note: The RPE elevation measurements can be affected by the presence, size, or extent ofgeographic atrophy, choroidal neovascularization, extensive epiretinal membrane, orvitreomacular traction. The user may evaluate the possible impact on the analysis byreviewing the individual B-scans and determining if the areas of RPE elevation overlap withthese other pathologies.

As with all retinal pathology, the user is encouraged to check the retinal segmentation inquestionable cases. View the horizontal tomogram and check the black and lavender linesindicating the borders of the RPE elevation measurement.

Note: The RPE Elevation algorithm was not tested on subjects who had geographicatrophy, choroidal neovascularization, or pigment epithelial detachments. Theperformance of the RPE Elevation algorithm on subjects with these conditions has notbeen determined. Since pigment epithelial detachments are elevations to the RPE, theAdvanced RPE Analysis may be of clinical use. See Appendix G for the performance ofAdvanced RPE Analysis measurements.

Note: Repeatability of measurements of RPE elevation are dependent on consistent andaccurate identification of the fovea location. The system has an automatic fovea finder. Theuser should check that the software was able to find the fovea location and evaluate if thelocation is correct. If the user determines that the location was not correct, the clinicianshould manually correct it.

Note: The minimum RPE elevation that the software will include in the quantitative result is19.5 μm. Drusen below this threshold are not included in the area and volumecalculations. In some cases, drusen may be observed in color fundus photographs that arenot seen in the Advanced RPE Analysis because either the drusen does not represent anyelevation, or because the drusen is accompanied by an elevation that does not meet theminimum threshold for detection. Only small, shallow drusen are likely to be missed.

Note: RPE elevation measurements are not meant to replace other means of clinicalevaluation such as color fundus photographs for drusen documentation and measurement.

Note: The clinical utility of this feature in therapeutic dry AMD trials has yet to beestablished.

Sub-RPE Slab

The Sub-RPE slab represents the summed reflectivity in the region below Bruch'smembrane. This slab indicates the fovea location with a dot and a circle corresponding to 5mm in diameter centered on the fovea. It also shows a red line from the fovea to theclosest area with sub-RPE illumination (6 in Figure 4-15).

The Sub-RPE Slab is shown as an overlay on the OCT Fundus image. The transparency ispreset, however you can adjust transparency on the analysis screen using the control belowthe slab (5 in Figure 4-15).



The automatic sub-RPE illumination segmentation is shown with an outline. Theboundaries can be toggled on or off. If the sub-RPE illumination segmentation outlines aretoggled on, these will become transparent to the same degree as the sub-RPE slab.

The Advanced RPE Analysis includes a horizontal tomogram. This tomogram shows the RPEelevation segmentation lines, but not the segmentation lines for the sub-RPE slabsegmentation. The segmentation lines may be toggled on or off.

Note: Repeatability of measurements of sub-RPE illumination are dependent on consistentand accurate identification of the fovea location. The system has an automatic fovea finder.The user should check that the software was able to find the fovea location and evaluate ifthe location is correct. If the user determines that the location was not correct, the clinicianshould manually correct it.

Note: This feature was tested on subjects who had lesion diameters no smaller than 1.25mm nor greater than 5 mm and who had no peripapillary atrophy or choroidalneovascularization. The performance of the Advanced RPE Analysis on subjects who do notmeet these criteria has not been determined. See Appendix G for the performance ofAdvanced RPE Analysis measurements.

Note: Increased sub-RPE illumination is not specific to geographic atrophy and can occurin any condition that causes RPE atrophy or thinning, absence or breaks, such as retinaldystrophies, scarring due to infections, and laser photocoagulation of the retina. Inaddition, poor signal strength, pigmentation of the fundus, and peripapilliary atrophy canoccasionally cause misleading sub-RPE illumination findings.

Note: The clinical utility of this feature in therapeutic dry AMD trials has yet to beestablished.



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Sub-RPE Illumination Editing

To edit the sub-RPE illumination:

1. Open an edit screen by clicking on the Segmentation Tool (shown at left). The screendisplays the sub-RPE illumination segmentation as a colored region on the sub-RPEslab. The current sub-RPE illumination segmentation becomes active for editing. Theedit screen also includes the OCT en face image with slice navigators and theHorizontal B-Scan tied to the navigator position.

Figure 4-16 Edit Sub-RPE Segmentation Dialog

2. Use one of the available edit tools (shown clockwise at left) to modify thesegmentation boundaries:

• Pencil: click and drag to draw with fine detail.

• Floodfill: adds gross detail. To fill in a full lesion, draw the boundary of the lesionwith the pencil tool or the floodfill tool, click on the floodfill icon, and then clickon the lesion to fill it in.

• Eraser: removed gross detail. To remove a large area, draw the boundary of thearea with the knife or eraser, click on the eraser icon, then click on the area toerase.

• Knife: click and drag to delete with fine detail.3. Once you have completed editing, click on the Apply button to complete the operation

and return to the Analysis screen with the updated segmentation. On the analysisscreen, the segmentation is shown as an outline around the area that had been filledin on the edit screen.

Note: You are able to edit the automatic sub-RPE illumination boundaries for the currentvisit only. If you want to edit the segmentation for the prior visit, highlight the scan for theprior visit and run the Advanced RPE Analysis. The prior visit then becomes the currentvisit, and you can edit segmentation.

Sliceindicators



Advanced RPE Analysis Screen 2

Figure 4-17 Advanced RPE Analysis - Screen 2

The analysis includes an image that combines the RPE Elevation Map and the sub-RPEillumination segmentation. The sub-RPE illumination segmentation is overlaid on the RPEElevation Map. The sub-RPE illumination segmentation is shown with an outline. Thisimage shows the fovea location with a dot marking and a circle corresponding to 3 mmand 5 mm diameter circles centered on the fovea. This image is superimposed on top of thefundus image.

• A caliper is available to measure distances on the RPE Profile Map. The measurementsmade with this tool will not be saved.

Calculated values: The analysis includes the following values as well as a calculation ofcurrent minus prior and percent change:

• Area of RPE elevations in 3 mm and 5 mm circle, with the unit of measure mm2

rounded up to one decimal place.• Volume of RPE elevations in 3 mm and 5 mm circle, with the unit of measure mm3

rounded up to two decimal places.• Area of sub-RPE illumination in 5 mm circle, with the unit of measure mm2 rounded

up to one decimal point. If no sub-RPE illumination is seen in the circle, the valueshown is 0.0.

• Distance measurement from nearest sub-RPE i llumination to fovea, with the unit ofmeasure mm identified and with values rounded up to one decimal place.

Note: The calculated difference does not consider test-retest variability.

The analysis and report indicate if the fovea has been found and the fovea location. If thefovea was not found, the analysis will center the measurement circles within the 6mm



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square. The user may edit the fovea location by clicking on the outer circle in the RPEElevation Map and dragging to the desired location. Or, the user may snap to the slicenavigator position.

A warning message will appear if the 5mm circle extends outside of the scan window.

A warning message will appear if the scan is too low in the B-Scan window.

Note: The Advanced RPE Analysis may occasionally identify RPE elevations or areas ofsub-RPE illumination in normal subjects. In a post-hoc analysis of 115 subjects from thediversified normative database, the software identified RPE elevations in the 5 mm circle in2.6% of the subjects, with a mean of 0.006 mm2 for area and 0.0002 mm3 for volume. Inthe same analysis, the software identified areas of sub-RPE illumination in 6.1% of thesubjects, with a mean area of 0.08 mm2.




HD 5 Line Raster Analysis

The Analyze screen for HD 5 Line Raster1 (Model 400 requires license) scan operates in thesame manner as described in on page 4-22, with the following exception. If a singlehigh-definition line scan image was acquired, then only one image is displayed, as shownin Figure 4-18.

Figure 4-18 Scan Analysis, HD Single Line Raster Scan

Note: The enhancement process combines data from multiple line scans. Registration ofthese line scans may result in reduced data at the edges of the images, which may show upas a thin, darker region with a sharp edge. This is a natural result of the enhancementprocess, but should only occur at the extreme edges of the image.

Note: By default, all screens associated with the HD 5 Line Raster and HD Single Line scanswill display the scans in color. Switching to black and white may improve the perceivedimage quality of the HD scans. Adjustments to brightness and contrast as well as switchingthe scans to black and white images are available using the existing menus and F9.

EDI Scan Analysis

Analyze the scan using the High Definition analysis protocol from the Analysis menu. If EDIwas used, a note will indicate this on the screen and report. Use the caliper tool tomeasure thickness of structures within the image on the analysis screen.

1. HD 5 Line Raster Analysis for Model 400 is an optional feature that may not be available in all markets, and when available in a

market, may not be activated on all instruments. If you do not have this feature and want to purchase it, contact Carl Zeiss Meditec.

In the U.S.A., call 1-877-486-7473; outside the U.S.A., contact your local Carl Zeiss Meditec affiliate or distributor.



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High Definition Image Analysis – 5 Line Raster

Figure 4-19 The Analyze Screen—High Definition Image Analysis

The ANALYZE SCREEN for High Definition Image Analysis (HDIA), Figure 4-19,enables you toview the five line scans of the 5 Line Raster scan. The scan angle, spacing and length areindicated above the images. The upper left viewport shows the saved fundus image withan overlay showing the location of each line scan. The currently selected line scan (middleline by default) is indicated in blue, the other lines in green. Below the fundus image arefive thumbnail images of each line scan. You can click on a thumbnail to view that linescan in large size on the right.

The applicable image display options are available when you right-click on an image —see Image Display Options During Analysis on page 4-11 for details.




right of scan display.

For diagonal scans in 5 Line Raster, left takes precedence over bottom, so that left of scanequals left of scan display and right of scan equals right of scan display.

1

2

3

4

1 Color Mode button 3 5 thumbnail images

2 Large image of selected line 4 Fundus image with 5 lines overlay


For horizontal scans, left equalsleft and right equals right. For alldiagonal scans in 5 Line Raster,left takes precedence overbottom. For vertical scans, left toright equals bottom to top.



Ganglion Cell OU Analysis

The Ganglion Cell OU Analysis1 measures the thicknesses for the sum of the ganglion celllayer and inner plexiform layer (GCL + IPL layers) using data from the Macular 200 x 200or 512 x 128 cube scan patterns. Comparisons are made to normative data (Appendix F).

Ganglion Cell OU Analysis Screen

Figure 4-20 Ganglion Cell OU Analysis Screen

The Ganglion Cell OU Analysis screen contains:• Thickness Map shows thickness measurements of the GCL + IPL in the 6mm by 6mm

cube and contains an elliptical annulus centered about the fovea.• Deviation Map shows a comparison of GCL + IPL thickness to normative data (red to

indicate where thinner than all but 1% of normals, yellow to indicate thinner than allbut 5% of normals).

• Thickness table showing average and minimum thickness within the elliptical annulus.• The Sectors in the lower portion of the screen divide the elliptical annulus of the

Thickness Map into 6 regions: 3 equally sized sectors in the superior region and 3equally sized sectors in the inferior region.

• Horizontal and Vertical B-scans. Note the slice navigator in the Vertical B-Scan is usedto adjust to a different Horizontal B-Scan and vice versa.

• The OCT B-scans are overlaid with segmentation lines. The purple line represents theinner boundary of the ganglion cell layer, which is also the outer boundary of the

1. Ganglion Cell OU Analysis is an optional feature that may not be available in all markets, and when available in a market, may not





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retinal nerve fiber layer. The yellow line represents the outer boundary of the innerplexiform layer. The maps shown and quantitative values reported represent thecombined thickness of the ganglion cell layer plus inner plexiform layers.

The screen allows editing the fovea location and navigating through the B-Scans.

If the fovea is not found, the fovea location and measurement circles are centered in the6mm square and the calculations made based on this position. You can manually move thefovea location and associated circle placements.

Note: If you move the fovea, the algorithm will be rerun using the new fovea.

The fundus image is not displayed on the analysis screen. You must go the the full pageview to see the fundus image in the Thickness or Deviation Maps.

Note: The GCA algorithm was tested on patients with glaucoma, but not other ocularconditions. The performance of this algorithm on patients with glaucoma and concomitantretinal disease, or retinal disease by itself involving the macula is not known, anddisruption of the inner retinal layers in such conditions may lead to atypical measurementsand deviation maps. The user should visually evaluate the image to determine if thesegmentation lines are correctly finding the inner boundary of the Ganglion Cell layer andouter boundary of the Inner Plexiform Layer in such cases.

Note: The repeatability of GCA measurements is dependent upon consistent and accurateidentification of the fovea location. The system has an automatic fovea finder. The usershould check that the software was able to find the correct fovea location and evaluate ifthe location is correct. If the user determines that the location was not correct, the clinicianshould manually correct it. If the software was unable to do so, the user should manuallymove the fovea location and associated circle placements to the correct location.



Single Eye Summary

The Single Eye Summary1 report combines information from the macular and optic disccubes and associated analyses. The goal of the report is to give the practitioner anoverview of key structural measures of the eye's posterior pole.

Figure 4-21 Single Eye Summary Analysis

The Single Eye Summary analysis appears as an available analysis when the user selects amacula cube scan (either 512x128 or 200x200) or an optic disc cube scan (200x200).Once the user selects the Single Eye Summary analysis, the system automatically processesdata from the other necessary scan. For example, if the Macula 512x128 is selected, thenthe system chooses the Optic Disc 200x200 from the same day for inclusion in the analysis.The user can also manually select the second exam, which may be from the same ordifferent date.

The Single Eye Summary analysis screen provides the following interactivity:

1. Single Eye Summary Report is an optional feature that may not be available in all markets, and when available in a market, may not



Macula Analysis ONH/RNFL OU Analysis

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5

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9

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11

1 Show/hide fundus lines icon 5 Slice through cube front 9 RNFL thickness graph with normative data

2 Macular Thickness Map 6 OCT fundus with optic disc and cup outlines and RNFL thickness deviation color coding

10 Control to choose angle of spoke extracted

3 OCT fundus image 7 RNFL thickness map with optic disc and cup masks 11 4mm B-Scan extracted from radial spoke

4 ETDRS grid for macular thickness with normative data comparison

8 Table includes RNFL and optic disc parameter with normative data comparison



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• Navigate through the OCT B-scans (macula and ONH).• Toggle between Macula B-scans in the same window.• Toggle between the Macula Cube B-scans and HD Cross Hair scans in the same

window.• Reset fovea location, which will update the data table and the ETDRS grid thickness

measurements.• Reset peripapillary RNFL circle location, which will update the RNFL and ONH

analysis.• Turn on and off the segmentation lines.• Turn on and off the disc and cup boundaries and fovea indicator.

The report provides the same information shown on the analysis screen in portraitorientation.

Single Eye Summary - Manual Selection

You are able to manually choose a different scan from any earlier date using the manualselection process.

1. At the top of the ANALYSIS screen, select the scan date and the scan you wish to use asthe more current scan (the scan information that will appear on the right side of thescreen).

2. Select Single Eye Summary - Manual Selection from the far right column. Thefollowing dialog box appears, showing a list of eligible scans.

Figure 4-22 Single Eye Summary dialog

3. Click on the scan you wish to include in the Single Eye Summary. A green check markwill appear next to the scan.

4. Click on Next to proceed. The window will collapse and the scan you chose willappear as the scan on the lside of the SINGLE EYE SUMMARY screen.



Reports and Printing

Cirrus enables you to generate analysis reports in color, which you can then either print onpaper or export in a number of electronic formats, such as PDF, TIFF or JPEG, to name afew. Cirrus provides two printing modes, stock or standard print mode and custom printmode. This section will describe each in turn.

Note: All report pages have a header with fields for (patient) Name, ID, Technician andInstitution (among other fields). (Institution name appears to the left of the ZEISS logo. SeeCreate an Institution Name on page 2-4). The layout of these fields limits the numberof characters that can be displayed on the report, even though you can enter additionalcharacters on the instrument when creating the Name, ID, etc. Specifically, reports candisplay 23 characters for ID (you can enter up to 32); 24 for Institution name (you can enterup to 36); 32 characters for Technician (you can enter up to 64); and 64 characters forName (you can enter up to 64). These character limits include spaces. If you createdpatient names, IDs, etc., longer than can be displayed on the report, be aware that theinformation you see on screen may not be unique to that patient.

Note: If analysis is edited and not saved, printing a report automatically saves the editedanalysis.

Note: The original analysis exam date and time always appears at the top of the printout.When an analysis is altered and saved, the original analysis date/time still appears at thetop of the page, while a new date/time for the alteration is printed in the Comments box atthe bottom of the page. If alterations are eventually deleted, that date/time stamp in theComments box is also deleted from the next printout.

Stock Print

The stock print mode provides a standard print layout for each kind of analysis. Stockprintout examples include:

• Normative Data Details Report, page 4-41• Macula Thickness Stock Printout, page 4-43• Macula Multi-slice Printout, page 4-44• Macula Radial Printout, page 4-45• Macular Change Analysis Stock Printout, page 4-46• Advanced Visualization Stock Printout, page 4-47• Advanced RPE Analysis Report, page 4-48• High Definition Image HD 5 Line Raster Stock Printout, page 4-49• Stock Printout for High Definition Image HD 5 Line Raster Using EDI

Mode, page 4-51• Ganglion Cell Analysis Stock Printout, page 4-52• Single Eye Summary Stock Printout, page 4-53



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When you mouse over or click on the Print button, four options, shown on the drop downmenu to the left, are available. If you want to print to an attached printer without goingthrough further options, simple click on the Print No Preview option. You can also savethe current analysis on display as a PDF file, which is also available from the Print Previewscreen.

If configured, you may select Export To DICOM to send the file to the DICOM Archive.

Selecting Print Preview presents a tool bar with other print options, as describedbelow.To make a stock print, select Print Preview to generate a report based on what iscurrently on screen. (The current cross-sections and/or surface maps will appear in thereport.) The system presents a print preview, as shown in Figure 4-23, of the currentanalysis report.

Figure 4-23 Print Preview Dialog

This screen also gives you the option to export in a number of electronic formats:

• PDF – Portable Document Format

• BMP – Bitmap

• GIF – Graphic Interchange Format

• JPEG – File Interchange Format

• PNG – Portable Network Graphics Format

• TIFF – Tag Image Format

• EMF – Enhanced Windows Metafile

• WMF – Windows Metafile

Click the appropriate button to generate a printout or to export the file to the format youchoose. After completion of the printing or export, click the X in the upper right corner ofthe screen to close the Reports Preview screen and return to the Analysis screen.

PDF All other options



Setting Print Configuration Defaults

There are three styles of printouts available for the Macular Cube scans: Macula Thickness,Macula Multi-Slice, and Macula Radial. You may choose one or more of these printouts foreach patient or set the defaults to print the same style(s) of printouts each time. To changethe default setting (which is Macula Thickness), open the Tools pull-down from the uppermenu bar and select Print Configuration, Figure 4-24. Select the desired printouts bychecking the appropriate boxe(s).

Figure 4-24 MTA Print Options

To change the printout parameters of the Macula Multi-Slice printout, open the PrintoutConfiguration window and select the Macula Multi-Slice parameters tab, Figure 4-25.You can choose the number of scans per each section of the macula scan.

Figure 4-25 Macula MultiSlice Parameters

The Central Region is comprised of the central 1 mm (1000 micrometers) of the cube. Thisis the equivalent of 500 micrometers above and 500 micrometers below the central B-scan.The Mid-Regions are comprised of the next 1.0 mm above and below the Central Region.The Outer Regions are the final 1.5 mm of area above and below the Mid Regions. Thesethree regions add up to the 6 mm height of the scan box and are equivalent to the EDTRSgrid spacing in the vertical direction.

You may choose the number of scans to print per region or indicate the spacing betweenthe scans. If you do not wish to print any scans for a particular region, enter “0” in theappropriate Number of Scans per Section field.



4-40

For the RNFL and ONH OU Report (Chapter 5), there is an optional second page thatpresents for each eye the optic nerve head en face image with cup and disc boundariesidentified and RNFL deviation information and TSNIT RNFL thickness summary profile. Thedefault setting is to print just the first page. To change the default setting:

1. From the Tools pull-down in the upper menu bar select Printout Configuration. Thefollowing dialog appears.

Figure 4-26 ONH Print Options

2. Select the desired printouts by checking the appropriate button. This configuration willpersist each time the report is generated.

For the HD 5 Line Raster analysis, you can print the selected line (single page) or print alllines (multiple pages). When Print All Lines is selected, each page diplays a different scanline in the larger format window. To change the current configuration:

1. From the Tools pull-down in the upper menu bar select Printout Configuration. Thefollowing dialog appears

Figure 4-27 Raster Print Options

2. Select the desired printouts by checking the appropriate button. This configuration willpersist each time the report is generated.



Normative Data Details Report

There is measurement variability for the macula parameters which may impact thenormative database color coding. If the true value is near the limit of what the softwareuses to determine the normative database color code, then it is possible that the colorcode could vary from exam to exam. When at least one parameter is close to a normativelimit, a blue icon button is displayed. When your cursor hovers over this icon button,the tooltip is displayed as shown below.

Figure 4-28 Measurement Variability Tooltip

If you click on the icon button, a Print Preview screen displays the Normative Data DetailsReport as shown below. The report can be printed from the Print Preview screen.

Figure 4-29 Macula Thickness Normative Data Details Report



4-42

The Normative Data Details Report displays the parameters of the analysis in the unitsmeasured and as a percentile from the normative database. In addition, the report displaysthe result minus the reproducibility limit, as well as the result plus the reproducibility limit,and their corresponding percentiles. Each of these measurements are presented with theappropriate normative database color code.

This report provides the ability to see how close a particular measurement comes to anormative limit cutoff by checking the actual percentile. In addition, the plus measurementvariability and the minus measurement variability values are also color-coded so the usercan determine if the original normative database designation would cross over to adifferent color level when considering the measurement variability. Due to measurementvariability, it is possible that the normative data color coding may change on subsequentvisits without representing a change in the condition of the patient. For more informationon measurement variability, please see Appendix G.

You may generate a Normative Data Details Report from the following analyses:• Macula Thickness Analysis• Ganglion Cell Analysis• Single Eye Summary• ONH and RNFL OU Analysis• RNFL Thickness Analysis

Note: ONH and RNFL OU Analysis and RNFL Thickness Analysis printouts will print twopages of the Normative Data Details Report as these reports are OU printouts (two eyes).

Note: The Normative Data Details Report is only available for the Diversified Database. Ifyou have licensed the Asian Normative Database, this report is not available.



Macula Thickness Stock Printout

The stock printout for Macula Thickness (Figure 4-30) includes all the information onscreen when you click Print.

Figure 4-30 Macula Thickness Stock Printout



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Macula Multi-slice Printout

An option to view the central fast B-scan and adjacent B-scans on a series of printouts isavailable when the Macula Multi-Slice printout1 is selected. This printout shows four fastB-scans per page, as shown in Figure 4-31, and you may select the number of B-scans todisplay in the multiple page printout. See Setting Print Configuration Defaults onpage 4-39 for information on changing the scan spacing and the number of scans to beprinted.

Figure 4-31 Macula Multi-slice Printout

1. Macula Multi-slice Printout is an optional feature that may not be available in all markets, and when available in a market, may not





Macula Radial Printout

The Cirrus HD-OCT provides a radial line printout option (Figure 4-32). Six B-scans areextracted at the meridians of 0 degrees, 30, 60, 90, 120, and 150 (300 x 330 in the lefteye). This printout is available with either the Macular Cube 512x128 or the Macular Cube200x200 scan.

As seen in the figure below, the direction of the arrow indicates the orientation of eachimage. These can be matched to the radial pattern overlay on the fundus image in theupper left portion of the printout. The retinal thickness map to the right shows these scansin relationship to the thickness map of the entire 512x128 Macular Cube.

The center of the radial pattern is dependent on the location of the center of the EDTRSGrid found on the Macular Thickness analysis screen. Moving the EDTRS Grid to a differentposition on the Macular Thickness analysis screen creates a different set of images on thisprintout. If the radial pattern is positioned such that a portion of the radial lines go outsidethe scan boundary, then no OCT data are displayed. For example, in the printout below,the top left-hand slice has a black edge on the left, where no data are displayed.

Figure 4-32 Macula Radial Printout



4-46

Macular Change Analysis Stock Printout

The stock printout for Macular Change Analysis includes all the information on screen inFigure 4-33 when you click Print.

Figure 4-33 Macular Change Analysis Printout



Advanced Visualization Stock Printout

The stock printout for Advanced Visualization, Figure 4-34, includes three images, onefundus image and two B-scan images. The upper left fundus image has an overlay showingthe area addressed by the cube scan and the two currently selected slices. The upper rightscan image shows the currently selected slow B-scan, corresponding to the magenta(vertical) scan line in the fundus image overlay. The largest, bottom scan image shows thecurrently selected fast B-scan, corresponding to the blue (horizontal) scan line in thefundus image overlay.

Figure 4-34 Advanced Visualization Stock Printout



4-48

Advanced RPE Analysis Report

The report contains elements from the analysis screen except for the tomograms. Slicenavigator lines are not displayed for the RPE Elevation Map and the Sub-RPE slab. Seebelow for a sample of the report.

Figure 4-35 Sample Advanced RPE Report



High Definition Image HD 5 Line Raster Stock Printout

The stock printout for the High Definition Image HD 5 Line Raster scans, Figure 4-36,includes a fundus image showing the placement of the line scans and all five scans, withthe currently selected scan larger (default print configuration).

When Print All Pages is selected on the print configuration dialog, each page diplays adifferent scan line in the larger format window. To change the default setting for thisprintout, see Setting Print Configuration Defaults, page .4-39.

Figure 4-36 Stock Printout for HD 5 Line Raster Scan



4-50

Stock Printout for High Definition Image HD 5 Line Raster Using EDI Mode

A sample of the stock printout is shown below:

Figure 4-37 Stock Printout for HD 5 Line Raster Using EDI Mode

InstitutionA

OSODHigh Definition Images: HD 5 Line RasterSignal Strength:

Exam Time:Exam Date:

Doctor:Gender:DOB:ID:

Name:

10/10

1:47 PM1/27/2011

Female6/30/195927-004

004, 27

Serial Number: 4000-1141

Length:Spacing:Scan Angle: 6 mm0 mm0°

Doctor's Signature CZMISW Ver: 6.0.0.319Copyright 2011Carl Zeiss Meditec, IncAll Rights Reserved

Page 1 of 1

CommentsAcquired using enhanced depth mode



High Definition Image Analysis (HDIA) Stock Printout

The stock printout for the High Definition Image Analysis (HDIA, for 5 Line Raster scans),Figure 4-38, includes a fundus image showing the placement of the line scans and allfive scans, with the currently selected scan larger.

Figure 4-38 Stock Printout for 5 Line Raster



4-52

Ganglion Cell Analysis Stock Printout

A sample of the Ganglion Cell Analysis Stock Printout is shown below.

Figure 4-39 Sample Ganglion Cell Analysis Stock Printout

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Single Eye Summary Stock Printout

The Single Eye Summary stock printout, Figure 4-40, shows a side-by-side comparison ofthe Macula and the ONH/RNFL OU Analyses.

Figure 4-40 Stock Printout for Single Eye Summary



4-54

Custom Print

The custom print mode enables you to generate a multi-page report from an AdvancedVisualization analysis showing as many scan images and fundus images with overlays(from the same scan) as you choose, as shown in Figure 4-41.

Figure 4-41 Example Custom Printout



To accomplish this, you must right-click and select Tag for print on each image you want toinclude in the report. When you are ready to generate the report, click the Tagged Imagesbutton above the upper right scan image on the ANALYSIS SCREEN for AdvancedVisualization (see Figure 4-12 on page 4-19). This opens the Tagged Images dialog,Figure 4-42.

Figure 4-42 Tagged Images Dialog

Tagged Images Dialog

The Tagged Images dialog enables you to change your image selection, create and view areport, save the report as a PDF, print it out, or save the selected images in multipleelectronic formats (see list on page 4-37). The layout and number of pages of the customreport depends on the number of images and the order you selected them for inclusion.

Note: The Tagged Images dialog is cumulative by scan while the current AdvancedVisualization analysis is open. That is, the images you tag remain tagged and available inthe Tagged Images dialog until you delete them or exit the analysis. The maximum numberof images that may be tagged for print is 18 (or 6 pages).

When you tag an OCT image or a fundus image that includes an overlay, Cirrusautomatically presents the image you select plus a companion fundus image fororientation or a text description of the overlay, respectively. Thus, for each image you tag,two images appear per row of the Tagged Images dialog, except for a fundus image thatdoes not include an overlay.



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• For OCT images, the companion fundus image has an overlay that highlights theposition of the slice or slab.

• For fundus images with an overlay, the companion text box describes the overlaycharacteristics.

Tagged Images Dialog Functionality

In the Tagged Images dialog, you have the following options:• Deselect images: All checkboxes are selected by default. Click a checkbox to deselect

its image and exclude it from the printout.• Tag All: Click to select all images.• Untag All: Click to deselect all images.• Make Report: Click Make Report to generate the report using the currently selected

images. The Report Preview Dialog opens (see Figure 4-23 on page 4-38). You willthen have the further options to print it out or save it as a PDF or TIFF or any of theother electronic formats listed.

• Save Images: Saves the currently selected images in BMP or JPG format in the locationyou select in the Save As dialog that appears. Each image in the pair is savedindividually; thus, two images are saved for each selected row. The systemautomatically appends an image number to the end of the name you enter.

• Delete Images: Deletes the currently selected images from the Tagged Images dialog.(This does not delete any of the data from the scan itself.)

• Close: Exits the Tagged Images dialog.

Export to DICOM Server

Once analysis is performed, any report that would normally be printed can be manuallyadded to the patient's electronic medical record as an encapsulated PDF document foreasy viewing.

From any analysis screen, click the Print icon and select Export to DICOM from the list.You will see a dialog showing that the DICOM archive is being accessed (Figure 4-43).

Figure 4-43 Exporting to DICOM Archive


Analyze Scans: RNFL and Optic Nerve 5-1

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Chapter Overview

This chapter explains how to use the retinal nerve fiber layer (RNFL) and optic nerve head(ONH) analysis portion of Cirrus HD-OCT software. Topics covered in this chapter include:

• ONH and RNFL OU Analysis, page 5-1• RNFL Thickness Analysis, page 5-15• Guided Progression Analysis - RNFL, page 5-17• Guided Progression Analysis - Optic Nerve Head, page 5-18• Advanced Visualization Analysis, page 5-30• Printouts, page 5-31

Note: See Appendix D for information on the RNFL Normative Database. See Appendix Efor information on the Optic Nerve Head Normative Database.

Access Analysis

To access analysis for the Optic Disc 200x200 Cube, click the Analyze button when it isactive; it is active when a patient record with saved exams is selected or is open. Usuallyyou will access it after selecting a patient from the ID PATIENT SCREEN. Initially, the analysisscreen shows four columns near the top (see Figure 5-1), which list:

• the patient’s exams by date (left column), with the most recent exam date selected bydefault;

• for the selected exam, the right eye OD scans (center left column) and left eye OSscans (center right column) by scan type;

• in the column on the right with which you can select among available analyses for theselected scan type, after you select a scan.

The image display portion of the screen is blank until you select a scan from the OD or OScolumn and then the desired analysis. Click to select any scan from the OD or OS list, thenclick on the analysis on the right. The corresponding analysis screen will appear in theimage screen below, after a few seconds.

ONH and RNFL OU Analysis

The ONH and RNFL OU Analysis1 (Figure 5-1) appears when you choose one Optic DiscCube 200x200 scan and then select ONH and RNFL OU Analysis in the right-hand column.The most recent Optic Disc Cube 200x200 for the other eye for the same visit (if available)is presented along with the scan you first chose, unless you manually select a different scanfor the other eye before clicking on ONH and RNFL OU Analysis. Once the ONH and RNFL

1. ONH and RNFL OU Analysis and ONH Normative Database are optional features that may not be activated available in all markets,

and when available in a market, may not be on all instruments. If you do not have this feature and want to purchase it, contact Carl

Zeiss Meditec. In the U.S.A., call 1-877-486-7473; outside the U.S.A., contact your local Carl Zeiss Meditec affiliate or distributor.

Analyze Scans: RNFL and Optic Nerve


5-2

OU Analysis is presented, you may choose any other Optic Disc Cube 200x200 scan fromthe same day if you wish to change scans.

Figure 5-1 ONH and RNFL OU Analysis

1 2

3

4

5

6

78910

11

12

13

14

15

1617

18

1 Calculation Circle Offset (horizontal, vertical) in mm relative to the OCT center 10 Drag to select an agular sample

2 Table includes Average RNFL Thickness, RNFL Symmetry, five optic disc parameters 11 Left and right eye neuro-retinal rim thickness

3 Toggles ONH slice indicator 12 Transparency slider

4 RNFL thickness map with optic disc and cup masks 13 Move purple circle to select a different center

5 B-scan extracted from RNFL Calculation Circle 14 4 mm B-scan extracted from ONH radial spoke

6 Average RNFL thickness along Calculation Circle for quadrants and clock hours 15 OCT fundus with optic disc and cup outlines

7 Control to choose angle of ONH spoke extracted 16 Signal Strength

8 Left and right eye RNFL thickness graph with normative data 17 Auto center button

9 Drag to select current A-scan sample 18 Normative Data Details



Image Quality Information• Signal Strength Value: This appears above the RNFL circle scan image. It ranges from

0-10, with 10 being maximum signal strength. When values are less than 6, the valueis below the acceptable threshold; when 6 or higher, the value is acceptable.

Note: The Signal Strength value applies to the entire cube scan.

• The Offset values indicate the location of the Calculation Circle in mm relative to thecenter of the scanned area (horizontal offset and vertical offset). If you move theCalculation Circle, the offset values will update.

Optic Nerve Head Parameters

This section describes how the optic nerve head calculations are performed and how thedata is displayed and summarized on the ONH and RNFL OU Analysis screen. This sectionmakes some reference to elements that include RNFL Thickness measurements, but thosemeasurements are described more fully starting on page 5-7.

Performing the Optic Nerve Head Calculations

The disc edge is determined by the termination of Bruch’s membrane. This is validated1 inthe literature. The rim width around the circumference of the optic disc is then determinedby measuring the amount of neuro-retinal tissue in the optic nerve. This differs from othermethods that determine the cup margin based on its intersection with a plane at a fixeddistance above the disc2,3.

In this method, the disc and rim area measurements correspond to the anatomy in thesame plane as the optic disc, while the 2D drawing is in the plane of the OCT en-faceimage, as would be seen by the clinician. In tilted discs, when the nerve exit is oblique, thedisc is viewed at an angle by the clinician, foreshortening the image. Therefore areasvisualized in the ophthalmoscopic examination, photographs, or other images will bereduced. Measuring the area in the same plane as the optic disc addresses thisforeshortening and better ties the results to the anatomy.

Illustrations of the Optic Nerve Head Calculations

The borders of the optic disc and the cup are illustrated in multiple places on the ONH andRNFL OU Analysis screen. The first place is on top of the OCT fundus image, as shown onthe left.

The base of this image is a sum of the reflectivity in each A-scan, in order to illustrate theanatomy scanned. Overlaid on this image is the deviation of the RNFL thickness from

1. Strouthidis NG, Yang H, Fortune B, Downs JC, Burgoyne CF. “Comparison of Clinical and Three-Dimensional Histomorphometric

Optic Disc Margin Anatomy,” Invest Ophthalmol Vis Sci. 2009; 50: 2165.

Strouthidis NG, Yang H, Fortune B, Downs JC, Burgoyne CF. “Detection of the optic nerve head neural canal opening within

three-dimensional histomorphometric and spectral domain optical coherence tomography data sets.” Invest Ophthalmol Vis Sci.

2009; 50:214.

2. Strouthidis NG, White EG, Owen VMF, Ho TA, Garway-Heath DF. “Improving the repeatability of Heidelberg retina tomograph and

Heidelberg retina tomograph II rim area measurements.” Br J Ophthalmol 2005; 89:1433.

3. Tan JC, White E, Poinoosawmy D, Hitchings RA.”Validity of rim area measurements by different reference planes.” J Glaucoma.

2004;13:245.



5-4

normal highlighted as red superpixels or yellow superpixels (see section on RNFLNormative Database). Also shown in purple is the Calculation Circle used for RNFLthickness measurements (see section on peripapillary RNFL thickness measurements,below). The optic disc outline is shown as a black line. The border of the cup is shown as ared line. The area between these two is the neuro-retinal rim area.

The second place the cup and disc boundaries are illustrated is on top of the RNFLthickness map (shown on the left). The interior of the cup is shown in light gray. Theneuro-retinal rim is shown in dark gray. The outer boundary of the neuroretinal rimcorresponds to the disc boundary.

The third place the cup and disc boundaries are illustrated is on the extracted OCT B-scan,as shown on the left. The B-scan data is extracted from a 4 mm radial cross-section thatcuts through the center of the disc. The segmented RPE layer is shown on the B-scan as ablack line, and the disc boundaries are shown in this 2D picture as black markers. Thesegmented ILM is shown as a red line, and the cup boundaries are shown in this 2D pictureas red markers. The location of the radial cross-section is shown as a turquoise line on topof the OCT fundus overlaid on the LSO fundus. The radial line can be chosen in 5ºincrements by clicking on the arrows to the right and left of the LSO spoke image.

On the ONH and RNFL Analysis screens, when you move the cursor to the selectedtomogram of the ONH, a tool tip will display the optic disc diameter value in mm.

Neuro-retinal Rim Thickness

The neuro-retinal rim thickness is also plotted for the left eye and right eye together, inunits of micrometers, as shown below.

You can use the blue line to select the sample of interest. There are 360 samples available.The text in the upper right corner shows the measurement of Neuro-retinal thickness inmicrometers for each eye at the given sample location.



Optic Nerve Head Summary Parameters

The information illustrated as described above is summarized into 5 parameters thatcharacterize the optic nerve head. These parameters are shown in the data table, as thebottom 5 lines of information.

The neuro-retinal rim area (mm2) is the summary of the darker gray neuroretinal rim regionshown on top of the RNFL thickness map. The lighter gray region on that same map is thearea of the cup (mm2); the total area of the disc is the area of the rim plus the area of thecup (mm2). The Average C/D Ratio is given by the square-root of the ratio of the area of thecup to the area of the disc. The Vertical C/D Ratio is the ratio of the cup diameter to thedisc diameter in the vertical meridian; VC/(VC+Vr1+Vr2). Cup volume is a 3D measurementdefined as the volume between a plane created by the cup outline at the vitreous interfaceand the posterior surface of the ONH. Its units are (mm3).

ONH summarydata



5-6

Illustration of Cirrus HD-OCT ONH Parameters

The illustration below (Figure 5-2) left (a) shows a sketch of a disc, as presented in the 2Den face view. Illustration (b) shows how this appears on the screen. The shaded regionrepresents the neuro-retinal rim area (mm2), the patterned region is the area of the cup(mm2); the total area of the disc is the area of the rim plus the area of the cup (mm2). TheC/D (cup-to-disc ratio) is given by the square-root of the ratio of the area of the cup to thearea of the disc. The Vertical C/D is the ratio of the cup diameter to the disc diameter in thevertical meridian; VC/(VC+Vr1+Vr2). Cup volume is a 3D measurement defined as thevolume between a plane created by the cup outline at the vitreous interface and theposterior surface of the ONH. Its units are (mm3).

Figure 5-2 ONH Parameters Illustrations

(a) (b)



RNFL Thickness Measurements

RNFL Calculation Circle and Peripapillary RNFL Thickness

Based on the location of the optic disc, Cirrus HD-OCT automatically places a purpleCalculation Circle of 3.46 mm diameter evenly around its center.

You can click and drag the Calculation Circle to adjust its placement, if you feel it is notoptimally placed. The optic disc parameters are recalculated under the assumption that theuser-selected center is the true center of the disc. You can click the Reset Calculation Circlebutton (for either eye) to return it to its automatically defined position.

Figure 5-3 Calculation Circle and extracted RNFL circle scan image

Note: For circular scans (as extracted in the ONH and RNFL OU Analysis and for theneuro-retinal thickness graph), left of scan starts at the most temporal point of the 3.46mmcircle, and travels around the circle starting in the superior direction, then nasal, theninferior, then back to temporal (TSNIT). This is clockwise for the right eye andcounterclockwise for the left eye.

Thickness Calculations

Layer-seeking algorithms find the RNFL inner (anterior) boundary and RNFL outer(posterior) boundary for the entire cube, excepting the optic disc. The system extracts fromthe data cube 256 A-scan samples along the path of the Calculation Circle that togethercomprise the RNFL scan image displayed (seen in Figure 5-3). Based on the RNFL layerboundaries in the extracted circle scan image, the system calculates the RNFL thickness ateach point along the Calculation Circle. The thickness data is plotted in the right and lefteye thickness graphs and the symmetry comparison graph.

The system also calculates, throughout the data cube (except the optic disc), the averageRNFL thickness for each A-scan in pixels 30 micrometers square. For comparison tonormative data, Cirrus combines 16 such A-scan pixels into superpixels composed of 16A-scans, 4 by 4 square. Since each A-scan covers a 30 micrometer square, Cirrus measuresthickness over superpixel squares 120 micrometers on a side.

The ONH and RNFL OU Analysis derives the rest of its elements from these two kinds ofthickness measurements: along the Calculation Circle and in superpixels. The rest of theRNFL elements are:

• RNFL Thickness Maps and Deviation from Normal Maps, page 5-8• TSNIT Thickness Profiles, page 5-10

Click Show/Hide Layers totoggle display of the RNFL innerand outer boundary layers andthe RPE layer in the extractedRNFL circle scan image.



5-8

• RNFL Data Table, page 5-10• Average RNFL Thickness Graphs, page 5-24

RNFL Average Thickness Values

These values report average thickness along the RNFLCalculation Circle by quadrants and clock hours. Thecolor associated with each measurement derives fromcomparison to the age-matched RNFL normative data.

A clock hour represents an average RNFL measurementover a 30° sector. The left eye clock hour labels aremirrored to match the right eye.

Thickness-Derived Analysis Elements

Cirrus uses the RNFL thickness measurements and ONH measurements to construct anddisplay the following elements.

RNFL Thickness Maps and Deviation from Normal Maps

These maps are based on all calculated thickness data for the cube. Each is furtherdescribed below. These maps also show optic disc measurements, as described above.

• RNFL Thickness Maps derive from pixel average thickness measurements and reportthickness using a color pattern, where cool colors (blues, greens) represent thinnerareas and warm colors (yellows, reds) represent thicker areas. The maps exclude theoptic disc, which appears solid blue. The color code expresses thickness ranging fromzero (blue) to 350 micrometers (white).

• Deviation from Normal Maps derive from superpixel average thickness measurementsand report the results of a statistical comparison against the normal thickness rangefor each superpixel, overlaid on the OCT fundus image. These maps apply the yellowand red colors (not the green) of the age-matched normative data to superpixelswhose average thickness falls in the yellow and red normal distribution percentiles.The green color of the normative data is not applied because most superpixels would



be green for normal patients, and the green color might obscure the anatomical detailin the underlying OCT fundus image. Any region that is not red or yellow falls within orabove normal limits.

A region that is yellow is thinner than all but 5% of normals. A region that is red isthinner than all but 1% of normals. The deviation map is created by binning individ-ual pixels of thickness measurement into superpixels consisting of 16 pixels (4 pixelsor 120 um to a side of each superpixel). There is a total of 50 by 50 (2500) superpixelsanalyzed, although superpixels at the edge or inside of the optic disc are not consid-ered and not shaded.

Note: There are several reasons why a particular region might differ from normal. Thedeviation map shows when a particular region of an eye is thinner than the same region ina population of normal subjects, but such deviation is not always due to pathological lossof RNFL, for any of the following reasons:

1. For each superpixel, 5% of normals will in generally be highlighted yellow, and 1% ofnormals will in general be highlighted red. Since each map consists of 2500superpixels, 125 pixels on average might be expected to be highlighted on eachnormal.

2. The normative database consisted of a population with a limited range of sphericalerror (-12D to +6D) and axial length (22 to 28 mm). Subjects with strongly myopic orhyperopic eyes may have a different distribution of measured RNFL thickness values,and may tend to flag more often than subjets who fall within the range of thepopulation used to create the normative database.

3. There is a wide variation in RNFL bundle anatomical distribution among the normalpopulation. A person with split-bundle anatomy or a person with a very tilted RNFLbundle pattern may show a deviation from normal anatomy without indicating thatthis person has lost RNFL.

Note: Changing the placement of the RNFL Calculation Circle changes the Deviation fromNormal Map, since each superpixel in the scanned area is defined relative to the center ofthe Calculation Circle. Meanwhile, the superpixel positions in the normative data aredefined relative to a fixed center based on the age-matched normative samples. Therefore,when you change the position of the Calculation Circle, you change the specific superpixelin the normative data against which each superpixel in the exam data is compared.

Note: Changing placement of calculation circle also changes the optic disc parametercalculations.

Note: When the temporal RNFL is very thin or entirely absent, the RNFL algorithm mayshow an artificial thickening of the RNFL in this area. If the temporal RNFL appears thickerthan normal, examine the algorithm lines as displayed on the extracted circular B-scan todetermine if the algorithm has correctly identified the RNFL.



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TSNIT Thickness Profiles

The TSNIT Thickness Profiles (TSNIT stands for Temporal, Superior, Nasal, Inferior, Temporal)display thickness at each A-scan location along the Calculation Circle and include as abackdrop the white-green-yellow-red color code based on the age-matched RNFLnormative data. The profile shows left and right eye RNFL thickness together, to enablecomparison of symmetry in specific regions. Drag the blue vertical line in the OU profile toselect the current A-scan sample from among the 256 samples.

✐ Tip: You cannot select every specific A-scan sample by dragging the verticalblue line. To select an individual A-scan, click (and release) the vertical blueline, then hold down the Ctrl key and press the left or right arrow key.

RNFL Data Table

The data table reports average thickness around the RNFL calculation circle. It also reportsa percentage calculation of thickness Symmetry between the eyes. The color associatedwith each measurement derives from comparison to the age-matched RNFL normativedata. The symmetry parameter is the correlation coefficient, converted to a percentage,that results from comparing the OD profile (256 points) with the OS profile (256 points).Normative data was collected for both eyes and the normal limits for this symmetryparameter were determined.

When the symmetry parameter is close to 100%, the two eyes have similar profiles. As oneprofile becomes different from the other, the reported symmetry value decreases. If there isno relationship between the two eyes, the symmetry approaches 0%. It is possible for thesymmetry to report a value below zero if the two profiles are very different, but this is rare.

The data table also reports optic disc parameters as described previously.

For completeness, it is necessary to introduce and explain the application of the RNFLNormative Database in these elements.

RNFL and ONH Normative Databases

The ONH and RNFL OU Analysis supports the clinician in identifying areas of the RNFL thatmay be of clinical concern by comparing the measured RNFL thickness to age-matcheddata in the Cirrus RNFL Normative Databases1. Normative data that is age-matched to thepatient appears when you perform the ONH and RNFL OU Analysis on patients at

RNFLSummaryData



least 18 years old. Data was not collected from subjects less than 18 years old. The samedata used to develop the RNFL Database was re-processed to develop normal limits foroptic nerve head parameters. As described further in Appendix E, the ONH normative datais matched to the disc area of the eye as well as the age of the patient.

The RNFL Normative Database uses a white-green-yellow-red color code, as seen in thelegend at left, to indicate the normal distribution percentiles. The color code applies toeach particular A-scan location in the TSNIT thickness graphs, to the quadrant, clock hourand whole-circle averages, and to the OD and OS columns of the data table. Amongsame-age individuals in the normal population, the percentiles apply to each particularRNFL thickness measurement along the Calculation Circle as follows:

• The thinnest 1% of measurements fall in the red area. Measurements in red areconsidered outside normal limits (red < 1%, outside normal limits).

• The thinnest 5% of measurements fall in the yellow area or below(1% yellow < 5%, suspect).

• 90% of measurements fall in the green area (5% green 95%).• The thickest 5% of measurements fall in the white area (white > 95%).

Note: Clinicians must exercise judgment in the interpretation of the normative data. Forany particular measurement, note that 1 out of 20 normal eyes (5%) will fall below green. Interpretation of the 1st Percentile: Values color-coded as “1st percentile” are lower than99% of the database sample, but may not extrapolate well to the general population withless than 300 subjects in the reference database. Results falling in this region should beinterpreted with caution.Interpretation of the 5th Percentile: Values color-coded as “5th percentile” are lower than95% of the database sample. The 95% Confidence Interval on the 5th Percentile extendsfrom the 2.5th percentile to the 7.7th percentile of the normative database.

Information icons displayed on the Analysis screen offer additional information aboutthe normative database limits. Hovering over the icon will display a tooltip, and clickingthe icon will create a printout of the additional information presented. See NormativeData Details Report on page 4-41 for more information.

Note: Normative data colors will not appear if the patient is less than 18 years old.

1. The Normative Databases are optional features that may not be available in all markets, and when available in a market, may not





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Distribution of Normals

The grey color, shown in the legend to the left, represents “Not applicable.” Values will beshown in grey when normative data is not applicable because the database has insufficientdata to match with the disc area.

The Distibution of Normals color scheme is used for both the RNFL and the Optic NerveHead analysis parameters. The table below clarifies how the color scheme is used for eachof the parameters.

Note: For patients under 18 years old, the legend and color coding is not displayed. Datawas not collected from patients under 18 years old.

There is measurement variability for the retinal nerve fiber layer and optic nerve headparameters which may impact the normative database color coding. If the true value isnear the limit of what the software uses to determine the normative database color code,then it is possible that the color code could vary from exam to exam. When at least one

Measurement Matched to Normal Based On

Grey White Green Yellow Red

RNFL

Average RNFL Thickness, RNFL Symmetry, RNFL Clock Hours, RNFL Quadrants, RNFL Thickness (graph)

Age Grey shading does not apply to RNFL measurements

The thickest 5% of measurements fall in the white area (white > 95%).

90% of measurements fall in the green area (5% < green < 95%).

The thinnest 5% of measurements fall in the yellow area or below (1% < yellow < 5%, suspect).

The thinnest 1% of measurements. Measurements in red are considered outside normal limits (red < 1%, outside normal limits).

Optic Nerve Head

Rim Area and Neuroretinal Rim Thickness (graph)

Disc Area and Age ONH Normative Database is not applicable if:

1) The disc area is larger than 2.5 mm2 or smaller than 1.33 mm2, or2) The Average or Vertical C/D Ratio is below 0.25, or3) The ONH Normative Database license has not been activated.

The largest 5% of measurements fall in the white area (white > 95%).

90% of measurements fall in the green area(5% < green < 95%).

The smallest 5% of measurements fall in the yellow area or below(1% < yellow < 5%, suspect).

The smallest 1% of measurements. Measurements in red are considered outside normal limits(red < 1%, outside normal limits).

Average C/D Ratio, Vertical C/D Ratio, Cup Volume

The smallest 5% of measurements fall in the white area (white > 95%).

90% of measurements fall in the green area(5% < green < 95%).

The largest 5% of measurements fall in the yellow area or below(1% < yellow < 5%, suspect).

The largest 1% of measurements. Measurements in red are considered outside normal limits(red < 1%, outside normal limits).



parameter is close to a normative limit, a blue icon button is displayed. When yourcursor hovers over this icon button, the tooltip is displayed as shown below.

Figure 5-4 Measurement Variability Tooltip

For more information on measurement variability, please see Appendix G.

If you click on the icon button a Print Preview screen displays the Normative Data DetailsReport, as shown below. The report can be printed from the Print Preview screen. Each eyewill print on a separate page for an OU Printout. See Normative Data Details Reporton page 4-41 for more information.

Figure 5-5 Normative Data Details Report



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Interactivity

For both the RNFL Thickness and Neuro-retinal Rim Thickness TSNIT graphs, as shown inFigure 5-6, the user can toggle between data for both eyes together, or separately forright eye or left eye. This is done by clicking on the grey button in the upper left corner ofthe Neuro-retinal Rim Thickness graph and RNFL Thickness graph, which will be labeled“OU,” “OD,” or “OS” depending on what the user has chosen.

Figure 5-6 Neuro-retinal Rim Thickness Graph



RNFL Thickness Analysis

Note: If you have a license for the ONH and RNFL OU Analysis, all of the informationavailable in the RNFL Thickness Analysis is available on that screen. The RNFL ThicknessAnalysis will not be available for instruments with ONH and RNFL OU Analysis enabled.

The RNFL Thickness Analysis1Figure 5-7 appears when you choose one Optic Disc Cube200x200 scan and then select RNFL Thickness Analysis in the right-hand column. The mostrecent Optic Disc Cube 200x200 for the other eye for the same visit (if available) ispresented along with the scan you first chose, unless you manually select a different scanfor the other eye before clicking on RNFL Thickness Analysis. Once the RNFL ThicknessAnalysis is presented, you may choose any other Optic Disc Cube 200x200 scan from thesame day if you wish to change scans.

Figure 5-7 RNFL Thickness Analysis

1. RNFL Thickness Analysis is an optional feature that may not be available in all markets, and when available in a market, may not be

activated on all instruments. If you do not have this feature and want to purchase it, contact Carl Zeiss Meditec. In the U.S.A., call

1-877-486-7473; outside the U.S.A., contact your local Carl Zeiss Meditec affiliate or distributor.

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1 Calcuation Cirrcle Offset (horizontal, vertical) in mm relative to OCT Fundus overlay center 8 Drag to select current A-scan sample

2 Average thickness along Calculation Circle for whole circle, quadrants, and clock hours 9 Right eye thickness graph with TSNIT normative data

3 RNFL circle scan extracted along 3.46 mm diameter Calculation Circle 10 RNFL Thickness Map

4 Deviation from Normal Map 11 Fundus image with OCT Fundus overlay, red Calculation Circle

5 Data Table 12 OCT Fundus overlay Transparency slider

6 Left eye thickness graph with TSNIT normative data 13 Signal Strength

7 Left and right eye thickness graph for symmetry comparison



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Note: Except for the following two graphics — Average Thickness Values and TSNITThickness Profiles — information under ONH and RNFL OU Analysis, which includesCalculation Circle and Peripapillary RNFL Thickness, RNFl Normative Database, andThickness-derived Analysis Elements also applies to the RNFL Thickness Analysis.

Average Thickness Values

These values report average thickness along the wholeCalculation Circle and by quadrants and clock hours. Thecolor associated with each measurement derives fromcomparison to the age-matched RNFL normative data.

A clock hour represents an average RNFL thicknessmeasurement over a 30° sector. The left eye clock hourlabels are mirrored to match the right eye.

TSNIT Thickness Profiles

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