The effects on ocular parameters with Orthokeratology lens wearing

Abstract

Objective To investigate changes in corneal morphology and corneal thickness,anterior chamber depth,the axial length in 1 month with orthokeratology lens wearing and discusses the mechanism of refractive error reduced by orthokeratology.Methods Thirty-three young myopic subjects wore reverse-geometry OK lenses every night for 1 month.Central corneal morphology and corneal thickness (CT) were measured by Pentacam (HR,Oculus,Inc.GmbH,Wetzlar,Germany),subjective refraction,and anterior chamber depth (ACD) and the axial length (AL) measured by IOL-Master (Zeiss Meditec,AG) were evaluated within 2 h after lens taken,Baseline and 1 day,1 week,1 month follow-up data were collected.The sagittal height of cornea (SH) was calculated according to Munnerlyn formula.Results A day later,subjective refraction significantly decreased 1.08±l.00D (P ＜0.000),and there was no statistical significance between 1 week and 1 month.The anterior curvature became flattened from 43.50±1.31D to 42.15±1.45D (P ＜0.000).The posterior curvature became steeped from-6.26±0.24D to-6.28±-0.22D (P ＜0.001).AL shortened 0.04±0.04mm (P ＜ 0.000).ACD experienced a statistically significant reduction after a week (P =0.013).CT had no clearly statistical significance after treatment.△ACD occupied 92％,124％,98％ of △AL (1 day,1 week,and 1 month,respectively).Conclusions Orthokeratology lens to reduce myopia occur within 1 week after surgery,visual acuity is stable after 1 week.The anterior corneal surface flattening is the main factor.After one month,the axial length is shorter,mainly due to the change of anterior chamber depth.Orthokeratology lens causes the overall bending of the anterior corneal surface flattening,it may still exist cornea back. Key words: Orthokeratology; Corneal thickness; Anterior chamber depth; Axial length; Corneal morphology