机译：AIM: To determine risk factors of regression and undercorrection following photorefractive keratectomy(PRK) in myopia or myopic astigmatism.·METHODS: A case-control study was designed in which eyes with an indication for re-treatment(RT) were defined as cases; primary criteria for RT indication, as assessed at least 9mo postoperatively, included an uncorrected distance visual acuity(UDVA) of 20/30 or worse and a stable refraction for more than 3mo.Additional considerations included optical quality symptoms and significant higher order aberrations(HOAs). Controls were chosen from the same cohort of operated eyes which had complete post-operative follow up data beyond 9mo and did not need RT. The cohort included patients who had undergone PRK by the Tissue-Saving(TS) ablation profile of Technolas 217z100 excimer laser(Bausch & Lomb, Rochester, NY, USA).Mitomycin C had been used in all of the primary procedures.·RESULTS: We had 70 case eyes and 158 control eyes,and they were comparable in terms of age, sex and follow-up time(P values: 0.58, 1.00 and 0.89,respectively). Pre-operative spherical equivalent of more than-5.00 diopter(D), intended optical zone(OZ)diameter of less than 6.00 mm and ocular fixation instability during laser ablation were associated with RT indications(all P values <0.001). These factors maintained their significance in the multiple logistic regression model with odd ratios of 6.12, 6.71 and 7.89, respectively.·CONCLUSION: Higher refractive correction(>-5.00 D),smaller OZ(<6.00 mm) and unstable fixation during laser ablation of PRK for myopia and myopic astigmatism were found to be strong predictors of undercorrection and regression.
展开▼
