1. Augenabteilung am St. Franziskus Hospital Münster The Role of the Epithelial Flap in EPI-LASIK and LASEK Suphi Taneri Travel Grant from B&L ASCRS Symposium, April 2-8, 2009, San Francisco

2. Augenabteilung am St. Franziskus Hospital Münster Purpose To evaluate the safety and predictability of EPI- LASIK using an EPI Separator head coupled to the Zyoptix XP microkeratome To elucidate the influence of the epithelial flap in EPI-LASIK and LASEK on visual recovery and pain perception.

3. Augenabteilung am St. Franziskus Hospital Münster Methods Ongoing prospective single-center study comparing 14 eyes of 7 patients treated with EPI-LASIK using the XP EPI Separator (Bausch & Lomb, Rochester, New York) to a control group of 14 eyes of 7 patients treated with LASEK. Each epithelial flap was clinically evaluated by its dimensions and completeness of epithelial separation. After laser ablation, epithelial flaps of one eye per patient were repositioned and the other one discarded. All eyes received a soft contact lens.

4. Augenabteilung am St. Franziskus Hospital Münster Methods Baseline: EPI- LASIK Age (Years) Corneal Thickness (µm) Sphere (D) Cylinder (D) SE (D) BCVA average Keratometry (D) Mean29550-3.81-0.67-4.140.9343.9 SD5461.500.481.580.100.8 Min20497-1.50 -6.630.742.6 Max40611-6.250.0-1.631.045.9 LASEK Age (Years) Corneal Thicknes (µm) Sphere (D) Cylinder (D) SE (D) BCVA average Keratometry (D) Mean34530-3.61-0.43-3.820.944.3 SD4251.420.441.570.131.7 Min20494-1.75-1.50-5.880.741.6 Max50588-5.75-0.25-2.01.047.0

5. Augenabteilung am St. Franziskus Hospital Münster Results HE stain of a discarded epithelial flap magnification 200x Microscopical examination showed complete epithelial separation

6. Augenabteilung am St. Franziskus Hospital Münster Results PAS stain of a discarded epithelial flap magnification 200x Microscopical examination showed complete epithelial separation

7. Augenabteilung am St. Franziskus Hospital Münster Results: Visual recovery Mean uncorrected visual acuity was slightly better in LASEK in the abscene of an epithelial flap. In Epi-LASIK mean uncorrected visual acuity was better if the flap had been repositioned (not significant).

8. Augenabteilung am St. Franziskus Hospital Münster Results: Development of pain perception Pain scores decreased continually from day 1 to day 4 in all groups and showed no significant difference between the 4 groups.

9. Augenabteilung am St. Franziskus Hospital Münster Results: Closing of the epithelium closed

10. Augenabteilung am St. Franziskus Hospital Münster Results: Haze and Epithelial Opacification Epithelial opacification was slightly higher with repositioned flaps (Fantes scale). LASEKMeanRange Flap repositioned0.43 ± 0.530-1 Flap discarded0.33 ± 0.520-1 Epi-LASIK Flap repositioned0.75 ± 0.270.5-1.0 Flap discarded0.33 ± 0.410-1.0

11. Augenabteilung am St. Franziskus Hospital Münster Conclusion Initial results indicate a safe and standardized fashion of performing a surface ablation using the Zyoptix XP Epi Separator. The role of the epithelial flap in surface ablation seems negligible in the first 3 months. Differences in late on-set haze formation may exist.