The I Kone Lens Manufactured in Boston XO ® Valley CONTAX Springfield, OR
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The I Kone LensManufactured in
Boston XO®
Valley CONTAX
Springfield, OR
Contact Lens Fitting Goals for Keratoconus
• Vision• Comfort• Corneal Health• Fit / Centration• Happy Patient
Selecting the Best Contact Lens Option
• Assessment of all of the Information– History includes lens failures & why ! – Spectacle Rx, Keratometry,
Topography– Size, shape, location of effected area
Modern Keratoconic Corneal Lenses
• Fitting – standardized– trial lens sets or topography – realistic increments
• Troubleshooting– logical, incremental changes– flexibility
A Systematic approach to:
I-Kone Design
• Anterior and posterior aspheric design.
• 10.4 mm, 9.6 mm, 8.8 mm • Boston XO®• Adjustable periphery• 14 lens fitting set
Diagnostic FittingI-Kone Keratoconus Design
Initial Base Curve fit on “Steep K” reading1. centration2. central clearance
Example:K’s 52.25 / 57.50 @ 45 5.92 mm (57.00 D)
9.6 mm diameter
Effect of
the
Base curve
Effect of
the
Base curve
I KoneEffect of Peripheral Curve
1 Step Flatter
2 Step Flatter
3 Step Flatter
The Keratoconic Cornea
• Assessment of ectatic area– Size – Location – Shape– Degree of Irregularity
The Keratoconic Cornea
• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin
Corneal Irregularity Keratometric View
The Keratoconic Cornea
• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin
Corneal IrregularityPhotokeratoscopic View
The Keratoconic Cornea
• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin
Corneal Irregularity Topographic View
Corneal Topography in Keratoconus
The Keratoconic Cornea
• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin
Advanced Keratoconus
The Keratoconic Cornea
• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin
Corneal Irregularity Slit Beam View
The Keratoconic Cornea
• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin
90 Degree Spin
Classifications of Keratoconus
• Shape– Mild < 45.00 D average K– Moderate 45.00 -> 52.00 D average K– Advanced 52.12 -> 60.00 D average K– Severe > 60.00 D average K
• Size– Nipple < 5 mm– Oval 5 -> 6 mm– Globus > 6 mm
Keratoconus
Nipple Shaped Keratoconus
Oval Shaped Keratoconus
Keratoglobus
Keratoconic Corneal Lens Options
The First Generation
• Soper (circa 1970)
– 1st significant KC design– Steep, fixed POZ
• McGuire Lens (circa 1980)
– Like Soper but multicurve
Keratoconic CornealLens Options
The Second Generation
• Valley Kone (Valley Contax, 1990)
– Smooth, continuous back surface• Rose K (Lens Dynamics, 1990)
– POZ varies with BC– Standardized fitting system
• Rose K II (Blanchard, 2005)
– Aspheric front surface to reduce Spherical Lens Aberration
Keratoconic Lens Optionsthe Third Generation
• I-Kone (Valley Contax, 2005)– Bi-surface aspheric– Balanced zone design
(central zones to fit cone area)– BC radius varied to achieve fit– Periphery fits non-ectatic area
Keratoconic Lens Optionsthe Third Generation
Balanced Zone Design• As BC radius steepens • POZ decreases• While Second Aspheric Width Increase• Eccentricity of Zones Increase
Advantages of fitting the I Kone Design
• Central Fit– extends the concept of 3 point touch– high eccentricity back surface spreads bearing
• Vision– front surface eccentricity to CANCEL out
aberrations induced by eccentric BC – and reduces other aberrations
• Comfort– reduced pressure points
• Corneal Health– Excellent tear flow
More advantages of fitting the I-Kone Design
• Aspheric Optics– Controls spherical aberration– Reduces lens mass
• Larger Diameter– Distributes weight more evenly across
corneal surface– Reduces glare / halos– Improves lens stability
The I Kone Lens14 Lens Diagnostic Set
Manufactured in
Boston XO®
Diameter Size: 9.6
Diopter Range: 44.00D to 70.00D
Valley CONTAX
Springfield, OR
800-547-8815
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