1. Corneal edema following Photorefractive Keratectomy (PRK) Gerald W Zaidman, MD, FAAO,FACS Professor of Ophthalmology Sarah E. Eccles Brown, BA Westchester Medical Center New York Medical College Valhalla, NY

2. THE AUTHORS DO NOT HAVE ANY FINANCIAL INTEREST IN THIS PRESENTATION

3. The purpose of this poster is to present a case of a patient with nearly total loss of endothelial cells and subsequent corneal edema following PRK with mitomycin

4. Case Report A 49 year old fireman underwent refractive surgery in May 2005 He had had flash burns to his eyes so he had no eyelashes or eyebrows His preoperative refraction was OD -4.75 – 2.50 x 40 OS -5.50 – 1.00 x 110

5. Case Report Corneal pachymetry was 503 OD and 502 OS Therefore his surgeon chose PRK + mitomycin – surgery completed without complication His exam in November, 2005 – VA, OD 20/40; Rx +0.75 – 0.75 x 30 VA, OS 20/25+; Rx plano PRK enhancement + mitomycin was performed

6. Case Report 5 days after enhancement cornea OD became acutely inflamed Patient referred-exam showed corneal stromal edema without ulceration – Figure 1 Eye healed; residual scarring and corneal thinning – VA = 20/200 Pacyhmetry = 391 OD, 467 OS; endo cell count OS=2700 PKP performed OD 5 months later

7. Figure 1

8. Pathology Excised corneal button demonstrated chronic stromal keratitis, loss of Bowman’s membrane, intact Descemet’s membrane, severe hypocellularity (almost complete absence) of endothelial cells

9. Discussion ► Myopic PRK may induce corneal scarring ► Mitomycin – C used since 2000 to prevent corneal haze following PRK ► Mitomycin toxicity has been reported after pterygium surgery but rarely after PRK

10. Mitomycin toxicity after PTK/PRK Pfister-after PTK, 6 day use of topical mito-C led to corneal edema Torres- mito-C seen in AC after PRK, after epithelial debridement Chang-rabbit study demonstrated dose dependent increase of corneal thickness after mito-c applied to corneas debrided of epithelium Morales-patients treated with mito-C after PRK had a significant loss of endothelial cells

11. Conclusions ► Mitomycin – C can penetrate into the anterior chamber ► Mitomycin – C in the anterior chamber can be toxic to endothelial cells ► Ophthalmologists should be careful about the use of Mitomycin – C in thin corneas with debrided epithelium because of an increased risk of endothelial toxicity

12. References ► Pfister RR. Cornea 2004; 23: 744-7. ► Torres RM, et al. JCRS 2006; 32: 67-71. ► Chang SW. JCRS 2004; 30: 1742-1750. ► Morales AJ, et al. AJO 2006; 142: 400-4.