Factors Associated with Low Visual Acuity after Orthokeratology Lens Removal and Myopia Control

Abstract

Objective: To assess the factors associated with low visual acuity after orthokeratology lens removal and the efficacy of myopia control. Methods: This was a retrospective study. Children who were examined and followed up for at least 6 months at Tongren Eye Care Center during April 2015 and January 2017 were enrolled in the study. Participants were divided into two groups based on their uncorrected visual acuity (UCVA) after removing orthokeratology lenses. Age, visual acuity, refraction, intraocular pressure, corneal curvature, e value, corneal diameter, pupil diameter, and axial elongation were compared between groups. Univariate and multivariate regression analysis were conducted to assess the factors associated with visual acuity. Results: Fifty children (96 eyes) participated in the study, with 52 eyes in the group with UCVA≤0.8 and 44 eyes in the group with UCVA>0.8. Mean age was 10.6±2.4 years. At baseline, mean spherical refraction was -3.62±1.18 D; mean cylinder refraction was -0.33±0.43 D; mean axial length was 25.18±0.75 mm. Using univariate analysis, and worse visual acuity was associated with longer axial length (b=-0.09, β=-0.29, P=0.003), higher spherical refraction (b=0.07, β=0.36, P 0.8, the difference was not significant. Conclusions: Longer axial length and higher spherical refraction are the main factors associated with visual acuity after orthokeratology lens removal. Despite worse visual acuity, myopia control is still effective. Key words: orthokeratology; myopia control; peripheral defocus