Single Step Transepithelial Photorefractive Keratotomy in Treatment of Moderate and High Myopia Six Months Outcome

Background: In this study the efficacy and safety of single step transepithelial PRK is evaluated on moderate and high myopia. The outcome of the procedure is compared like SER, residual astigmatism, HOAs and haze. Aim of Study: Trans PRK is a laser-assisted method for epithelial removal, was introduced as an alternative to conventional PRK which is based on mechanical debridement of the corneal epithelium. Patients and Methods: Patients were divided into two groups moderate and high myopia both groups where chosen based on inclusion criteria. Patients where operated using the same laser machine. The parameters and software were slan-dered for the two groups. The machine was programed for laser ablation of the corneal epithelium which was calculated as standard 50-60 micron followed by laser ablation of the stroma based on refractive errors and stromal thickness all were in single step. The postoperative regimen for the two groups was the same and the follow-up period start from day one tell the sixth month. Results: Forty eye in each group in high myopia group patients gain one line are 25% while in moderate myopia group patients gain one line are 42% and 12.5% for two lines. The UDVA by the sixth month was 15% 20/25,65% 20/20, and 20% 20/16 while in moderate myopia it was 2.5% 20/25, 50% 20/20,30% 20/16 and 17.5% 20/12.5. The residual errors for high myopia were 75%±0.50 and 100%±1.00 while in moderate myopia 82.5%±0.50 and 100%±1.00. the residual astigmatism was 35%±0.25 and 100%±0.50 in high myopia while it was 52.5%±0.25 and 100%±0.50 in moderate myopia. Conclusion: Transepithelial photorefractive keratotomy is a safe and effective procedure in treating moderate and high myopia considering the postoperative recovery period and haze.