Transepithelial photorefractive keratectomy for myopia: effect of age and keratometric values

Abstract

AIM: To investigate demographic and preoperative factors increasing the risk of ametropia following transepithelial photorefractive keratectomy (transPRK) in myopia and myopic astigmatism. METHODS: This retrospective cohort study included myopic eyes (-0.50 to -8.75 D) with or without astigmatism (up to 3.50 D) enrolled at Dr. Yap Eye Hospital Yogyakarta. TransPRK was performed using Technolaz 217z100 excimer laser. Subjects were clustered into ametropia and emmetropia group based on uncorrected distance visual acuities (UDVA) 3mo post-operatively. Multiple preoperative and intraoperative parameters were analyzed using Logistic regression to obtain their effect on ametropia risk following transPRK. RESULTS: A total of 140 eyes of 87 consecutive subjects were studied. Prevalence of ametropia following transPRK was 20 (14.29%) eyes. Subjects in ametropia group were significantly older than the emmetropia group (31.80±14.23 vs 18.88±2.41, respectively; P<0.001). Bivariate Logistic regression analysis showed that older age (OR=1.23), higher preoperative spherical equivalent (>-6 D; OR=12.78), steeper anterior keratometric readings (Kmax>45 D and mean K>44 D; OR=4.28 and 4.35, respectively) increased the risk of ametropia following transPRK. Adjusted multivariate Logistic regression analysis showed that age was the strongest predictor for the incidence of ametropia following transPRK. Complications of transPRK were overcorrection, suspected posterior keratoectasia and accommodation insuffiency. CONCLUSION: Older age can be the strongest factor for increasing ametropia risk following transPRK. Cut-off points of Kmax and mean K at 45 and 44 D respectively are proposed as the predictors for ametropia following transPRK.