Dose-response for Mitomycin-C in prevention of haze in photorefractive keratectomy for high myopia: Six month preliminary results CDR Elizabeth M. Hofmeister, MD* CDR Frank M. Bishop, MD* CAPT David J. Tanzer, MD** Sandor Kaupp, MS* CAPT (ret) Steve Schallhorn, MD*** Navy Refractive Surgery Center, San Diego Financial disclosures: * Dr. Hofmeister, Dr. Bishop, and Mr. Kaupp have no financial disclosures. ** Dr. Tanzer is affiliated with TLC Laser Center *** Dr. Schallhorn is a consultant for AMO

Disclaimer The views expressed in this presentation are the personal views of the authors and not the official views of the U.S. Navy or the Department of Defense.

Purpose To investigate the safety and efficacy of Mitomycin- C (MMC) 0.1 mg/ml in preventing haze after PRK for high myopia at three different dose durations: one minute thirty seconds fifteen seconds

Methods Randomized, prospective, placebo controlled, masked trial. Patient eligibility: Patients were recruited from those who selected PRK independently and those who were deemed ineligible for LASIK due to an inadequate estimated residual beds thickness. Mean spherical equivalent to 8.00 and no more than 1 diopter of anisometropia No medical contraindications for refractive surgery Age > 21.

Methods Surgical methods: Epithelial removal with rotating brush VISX S4 platform, wavefront guided ablation profiles with iris registration Following excimer laser ablation, the study eye was treated with Mitomycin-C (MMC) 0.1 mg/ml soaking a 6 mm circular sponge, the control eye was treated with a 6 mm sponge soaked with balanced salt solution. A bandage contact lens was placed in both eyes, followed by topical gatifloxacin, topical ketorolac, and topical fluorometholone. Fluorometholone prescribed in a two month tapering dose schedule. The patient and providers doing post op checks are masked as to which eye received MMC. Study data collected: Preoperative and postoperative endothelial cell counts by confocal microscopy Preoperative and postoperative refractive error Preoperative and postoperative uncorrected and best corrected visual acuity Postoperative haze scores using a five point scale (0-4)

Methods: Study data One year study: Data collected preoperatively and at 1, 3, 6, and 12 months Endothelial cell counts: confocal microscopy Haze scores: 0, 1, 2, 3, 4 Visual acuity/contrast acuity Manifest refraction

Results: Preoperative Characteristics Group A 60 seconds Group B 30 seconds Group C 15 seconds Number of patients 1099 Mean pre-op sphere (range) D (-5.00 to -7.25) Std dev: D (-4.50 to -7.75) Std dev: D (-4.25 to -8.50) Std dev: 1.21 Mean cylinder-0.79 D (-0.00 to -1.50) Std dev: D (-0.50 to -3.50) Std dev: D (-0.25 to -1.50) Std dev: 0.35 Sex: male female 7 patients 3 patients 7 patients 2 patients 6 patients 3 patients Average age (range) 32.8 years (23- 53) 32.9 years (25 -43) 33.1 years (25-43)

Results: Haze scores A= 60 sec. B= 30 sec. C= 15 sec.

Results: Endothelial Cell Counts Change in endothelial cell count One month counts Six month counts A= 60 sec. B= 30 sec. C= 15 sec.

Study Conclusions At six months follow-up, there was no difference in haze scores in eyes of high myopes that received mitomycin and those that didn’t. Mitomycin-C had no effect on endothelial cell counts. Final twelve month evaluations are pending.

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