Corneal Endothelial Cell Changes after Photorefractive Keratectomy for Low to Moderate Myopia With and Without Mitomycin-C

Abstract

Background: Mitomycin-C was suggested for application during surface ablation procedures to reduce post-operative haze formation. It can effectively reduce haze formation and hence, improve the predictability of visual outcomes following refractive surgery. Despite these advantages, MMC can potentially damage all three main corneal cell types including epithelial (differentiated epithelium and limbal cells), stromal (keratocytes), and endothelial cells. Aim of Study:To investigate the croneal endothelial cell changes after Photorefractive Keratectomy (PRK) with and without Mitomycin-C 0.02% for low to moderate myopia. Patient and Methods:This prospective, randomized, comparative study included 60 eyes of 30 patients who were chosen from Ophthalmology Clinic at Tanta University Hospital and Shorouk Laser Vision Correction Centre for 6 month from December 2017 to May 2018 and scheduled for Photorefractive Keratectomy (PRK) using193nm wavelength excimer laser system Allegretto EX500, (Wave Light Technologie., USA). These patients were randomly divided into two groups. Group (A) were scheduled for (PRK) with adjunctive mitomycin-C 0.02% and patients of Group (B) were scheduled for (PRK) without mitomycin-C. Informed consents were obtained from all study participants.Results: In Group A the mean Endothelial Cell Density (ECD) was 2891.61 ± 272.41 and at three months after surgery was 28 13.04±276.55cells/mm 2 (p=0.289), pre-operative mean of Coefficient of Variation (CV) was 34.87 ± 4.37 and postoperatively was 34.70 ±4.06 (p=0.877), the pre-operative mean of Central Corneal Thickness (CCT) was 523.00 ±26.14 µ and 467.36 ± 40.61 µ post-operatively (p=0.001), the mean of hexagonality pre-operatively was 64.26 ±8.64% and 59.96 ± 8.15% post-operatively (p=0.059) which was statistically insignificant. In Group B the mean Endothelial Cell Density was (ECD) 2874.50±314.48 and at three months after surgery was 2777.23±302.44cells/mm 2 (p=0.227), pre-operative mean of Coefficient of Variation (CV) was 33.49 ± 4.98 and postoperatively 33.55 ± 4.10 (p=0.962), pre-operative mean of central corneal thickness was 538.03 ± 26.03 and 484.50 ± 20.55 post-operatively (p=0.001), the mean of hexagonality preoperatively was 63.00±7.74 and 61.43±7.29% post-operatively (p=0.423). Conclusions:There's no significant effect on endothelium in patients underwent to PRK in low to moderate myopia with or without mitomycin-C. We can't judge the same results for patients with high myopia because the ablation depth will be more and theoretically the diffusion of mitomycin-C to endothelium would affect its function or count.