Microkeratome Assisted Superficial Anterior Lamellar Keratoplasty: A Prospective Interventional Case Series Michelle Attzs Sathish Srinivasan Department.

Microkeratome Assisted Superficial Anterior Lamellar Keratoplasty: A Prospective Interventional Case Series

Michelle Attzs

Sathish Srinivasan

Department of Ophthalmology, University Hospital Ayr, Scotland

The authors have no financial interests to declare

To report indications, visual and refractive outcomes of patients following microkeratome assisted superficial anterior lamellar keratoplasty (SALK)

PURPOSE

METHODS

1. Interventional case series of nine eyes of nine patients, with anterior corneal pathology, who underwent pre operative anterior segment optical coherence tomography (AS-OCT) with either Visante (Carl Zeiss Meditec, Inc, USA) or Cirrus (Carl Zeiss Meditec, Inc, USA)

2. All surgeries were performed by a corneal surgeon (SS)

3. Depth of pathology, thickness of donor lamellar disc used, pre and postoperative uncorrected (UDVA) and corrected distance (CDVA) visual acuities; and complications were evaluated

SURGICAL TECHNIQUE

1. Depending on the depth of pathology, as assessed by AS-OCT, a 200, 250 or 300 micron head microkeratome (Moria, France) was used to remove the pathological anterior lamellar from the recipient cornea

2. The donor cornea was mounted on an artificial anterior chamber (Moria, France)

3. A same sized microkeratome (with freshly disposable blade) was used to prepare the donor anterior lamellar button

4. A donor anterior lamellar button of the desired thickness, with an overall diameter of 9.25mm, was provided

5. The donor anterior lamellar lenticule was secured to the host stromal bed with a combination of eight 10-0 nylon interrupted sutures and fibrin glue

6. A bandage contact lens was positioned on the eye at the end of the procedure

Patient Age Sex Indication for surgery

Depth of pathology(microns)

Pre op UDVA

Pre opCDVA

Post op UDVA

Post opCDVA

Further surgery

1 70 M Anterior stromal scar- HSV keratitis

150 0.78 0.48 2 0.78 DALK due to underestimation of depth of pathology by AS OCT

2 29 M Anterior stromal scar- HSV keratitis

160 0.78 0.18 0.48 0 -

3 48 M Ant/Mid stromal scar- CL related infectious keratitis

144 0.78 0.3 2 0.6-

4 46 M Lattice dystrophy

150 0.6 0.6 0.78 0.48 Interface infectious keratitis and subsequent DALK

5 53 F Anterior stromal scar - CL related infectious keratitis

120 0.48 0.18 0.6 0.3-

6 40 F Meesmann corneal dystrophy

U/A 2 2 2 2-

7 80 M Anterior stromal scar- HSV keratitis

240 2 0.78 0.78 0.6 -

8 44 F Anterior stromal scar- HSV keratitis

190 2 2 2 2 PK due to underestimation of depth of pathology by AS OCT. Subsequent early rejection

9 30 M Granular dystrophy

U/A 1 0.3 0.48 0.6 -

RESULTS

1. Mean age of cohort 49 ± 17 years (range 29 – 80)

2. Average depth of pathology on AS-OCT was 165 ± 39 microns (range 144 – 240 microns) (including patients where AS-OCT could assess depth of pathology)

3. Inaccurate estimation of depth of pathology by AS- OCT with two cases resulted in a further deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) (Patient 1 and 8, respectively)

4. One case developed interface infectious keratitis, and required a subsequent DALK, after removal of the SALK and treatment with high dose antimicrobial treatment (Patient 4)

5. AS-OCT was unable to estimate the depth of pathology in cases of corneal dystrophy

RESULTS6. Pre operative mean UDVA and CDVA, of all patients who

underwent surgery, was 1.16 logMAR and 0.76 logMAR, respectively

7. At 6 months, post operative mean UDVA and CDVA was 1.06 logMAR and 0.68 logMAR, respectively (excluding patients who required further surgery , n=3)

CASE 1

48 year old male with central corneal scar of OD due to contact lens related infectious keratitis. AS-OCT shows a pathology depth of 144 microns. Pre op UDVA was 0.78 logMAR and CDVA was 0.3 logMAR. A 200 micron microkeratome was used for donor and host cornea.

CASE 1

There were no intra or post operative complications. Post operative slit lamp examination demonstrates no residual pathology on the stromal bed, and this is confirmed by AS-OCT. Post op UDVA was 2 logMAR and CDVA was 0.6 logMAR. This patient went on to have cataract surgery 2 years later, which resulted in a UDVA and CDVA of 0.18 logMAR.

CASE 2

29 year old male with central corneal scar of OD secondary to herpes simplex virus keratitis. AS-OCT shows a pathology depth of 160 microns. Pre op UDVA was 0.78 logMAR and CDVA 0.18 logMAR. A 300 micron microkeratome was used for donor and host cornea.

CASE 2

There were no intra or post operative complications. Post operative slit lamp examination demonstrates no residual pathology on the stromal bed, and this is confirmed by AS-OCT. Post operative UDVA was 0.48 logMAR and CDVA was 0.0 logMAR.

CONCLUSIONS

1. AS – OCT is a useful tool for assessing the depth of anterior corneal pathology in the majority of cases

2. Microkeratome assisted superficial anterior lamellar keratoplasty (SALK) is safe and effective for the surgical management of anterior corneal pathologies