Effect of four types of refractive correction on myopia progression in Chinese children

Abstract

Objective To compare axial length growth and myopia progression among myopic Chinese children wearing single-vision spectacle lenses (SVs),orthokeratology lenses,rigid gas-permeable contact lenses (RGPCLs) or progressive-addition spectacle lenses (PALs) and to evaluate their efficacy in the control of myopia.Methods This was a prospective,non-randomized and case-controlled clinical study.One hundred and four myopic children aged 9 to 15 years were enrolled in this study.Subjects' refractive conditions ranged from-0.50 to-4.50 DS with astigmatism less than 2.00 DC.Each subject was allocated to one of four correction groups (SV,orthokeratology lens,RGPCL,or PAL),and followed for 24 months.Twenty-one children were fitted with SVs,24 with orthokeratology lenses,30 with RGPCLs,and 29 with PALs.Cycloplegic refraction,axial length and topography measurements were performed.Data were analyzed using ANOVA,repeated measured ANOVA and a chi-square test.Results At baseline,the four groups were comparable in terms of age,k-reading,and axial length,exception for spherical equivalent refractive error (F=6.920,P＜0.01).The RGPCL group (-3.04±0.79 D) was more myopic than the SV (-2.35±0.80 D),orthokeratology lens (-2.33±1.02 D) and PAL (-2.15±0.60 D) groups at baseline.Axial length increased significantly over 2 years (F=315.912,P＜0.01) for the SV group (0.57±0.23 mm),orthokeratology lens group (0.31±0.20 mm),RGPCL group (0.51±0.30 mm) and PAL group (0.61±0.27 mm),with a significant interaction between time and groups (F=4.175,P＜0.01) and significant differences among the four correction methods (F=6.599,P＜0.01).Axial elongation was slower in the orthokeratology lens group compared to the others,but there were no differences among the SV,RGPCL and PAL groups.Myopia progressed significantly over 2 years (F=121.840,P＜0.01) for the SV group (-1.23±0.64 D),RGPCL group (-0.82±0.69 D) and PAL group (-1.12±0.53 D),with insignificant interaction between time and group (F=l.300,P＞0.05)and no significant differences among those three correction methods (F=2.987,P＞0.05).Conclusion For the efficacy of myopia control,the orthokeratology lens is most remarkable.Rigid gas permeable contact lenses and progressive-addition lenses are not more effective for myopia control than single-vision spectacle lenses. Key words: Single-vision spectacle lenses;  Orthokeratology;  Contact lenses,rigid gas-permeable; Progressive-addtion lenses;  Myopia control