Predictors of myopic photorefractive keratectomy retreatment

Purpose To determine the factors associated with retreatment after photorefractive keratectomy (PRK) in myopic eyes. Setting Care-Vision Laser Centers, Tel-Aviv, Israel. Design Retrospective cohort study. Methods A large database on myopic PRK with mitomycin-C (MMC) performed from 2005 to 2012 was studied. Patients were divided into 2 groups according to whether they had retreatment. Multiple preoperative and intraoperative parameters were analyzed for association with retreatment. Results A total of 9699 eyes of 9699 consecutive patients were studied. The mean age was 25.9 years ± 7.3 (SD); 54.1% were men. The mean preoperative subjective spherical equivalent and astigmatism were −4.30 ± 2.18 diopters (D) (range −0.5 to −13.0 D) and 0.77 ± 0.83 D (range 0 to 6.0 D), respectively. Two hundred twenty-three eyes (2.30%) were retreated. The 2-year retreatment rate decreased from 42 (6.17%) for primary PRK treatments done in 2005 to 2 (0.10%) for primary PRK done in 2012 (R² = 0.79, P <.001). Multiple binary logistic regression analysis showed that transepithelial PRK, astigmatism equal to or higher than 3.5 D, and surgeon factor significantly increased the odds of retreatment. Additional parameters significant on univariate analysis alone included age older than 40 years, low preoperative sphere, maximum ablation depth less than 45 μm, preoperative corrected distance visual acuity better than 20/20, MMC application longer than 40 seconds, and optical ablation zone smaller than 7.0 mm. Conclusion The retreatment incidence of PRK has continued to decrease. High astigmatism and transepithelial PRK were associated with increased myopic PRK retreatment rates.