The influence of overnight orthokeratology on corneal topography and vision quality

Abstract

ObJective To investigate the changes and daily fluctuation of corneal shape and ocular aberrations in myopic eyes undergoing overnight orthokeratology,and to analyze the relationship among comeal shape,ocular aberrations and vision.Methods Seventeen young myopic subjects (34eyes) were recruited with myopia from-0.75D to-4.50D.Subjective refraction,uncorrected visual acuity,ocular aberrations,corneal curvature,corneal thickness and contrast sensitivity were performed at baseline and 1 day,1 week and 1 month after lens were wom.Except for baseline,all the parameters were collected at three different times during the day,immediately following lens removal and 4,8 hours after lens removal.Results Orthokeratology significantly improved logMAR uncorrected visual acuity from 0.91±0.30 to 0.02±0.16 (P ＜0.05),decreased the corneal curvature of 3mm from 43.53±1.11D to 41.39± 1.14D (P ＜0.05).But significantly increased ocular higher-order aberrations and decreased contrast sensitivity function.The AULCSF decreased from 1.43±0.07 to 1.33±0.14 (P ＜0.05).The daily fluctuations of visual acuity and AULCSF were stable after 1 week.But the significant changes of daily fluctuations on comeal curvature,corneal thickness and ocular aberration were still observed after 1 month (P ＜0.05).Conclusions Overnight orthokeratology is effective in the reduction of myopic refractive error.Although the regression of corneal shape and ocular aberrations existed in the daytime after one month,vision quality changes remain stable. Key words: Overnight orthokeratology; Uncorrected visual acuity; Corneal curvature; Ocular aberration; Contrast sensitivity function