• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.65-73
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• 2008

Purpose: The purpose of this study is to investigate the effect of age in the response to long-term overnight orthokeratology (OK) lens wearing. Methods: Among volunteers, ninety-five healthy subjects who had no eye diseases and could wear OK contact lens at least for 8 hours every day were divided into three groups children, youngsters and young adults. Unaided logMAR visual acuity, refractive error, apical corneal radius, corneal asphericity and central corneal thickness were measured with different period; before and after one day, one week, two weeks, one month, three months and six months of OK lens wear. Paired student t-test, ANOVA analysis and Pearson correlation were used with a critical p value of 0.05 for statistical analysis. Results: All groups showed statistically significant (p<0.001) improvement in unaided visual acuity, a trend for flattening in the apical corneal radius, decrease in central corneal thickness and less prolate after OK lens wear. The child group showed significantly rapid change (p<0.001) in visual acuity, and apical corneal radius showed that they reached the targeted refractive change earlier compared with youngster and adult groups. The visual effect of OK lens was significantly related with the change in central corneal thickness after long-term OK lens wear, especially in child and youngster group, and central corneal thickness were highly correlated with the targeted refractive change. Conclusions: Visual acuity change is statistically correlated with the central corneal thickness change, which is highly correlated with targeted refractive change in the long-term orthokeratology and younger lens wearers showed a rapid response to OK lens wear, suggesting a reduced epithelial response with increasing age. The results found this study extends our understanding and development in the long-term orthokeratology.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.7-15
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• 2009

Purpose: To investigate the corneal recovery after discontinuing orthokeratology (OK) lenses wear in children for long-term period. Methods: Among the OK lens wearers who wear over 8 months and showed successful refractive correction, 25 subjects were selected who want to discontinue the OK lenses. Uncorrected visual acuity, refractive correction, corneal curvature (Sim K), central corneal thickness and corneal eccentricity were measured during the OK lens wearing period and after discontinuation for 1 month. Results: Uncorrected visual acuity and corneal shape had remodeled significantly during the OK lens wear and recovered significantly during the first week of discontinuation. Uncorrected visual acuity and refractive correction had achieved full recovery 2 weeks after discontinuation of lens wear and were highly correlated with the changes in corneal thickness. But corneal shape recovered slowly, eccentricity had recovered fully after 1 month and corneal curvature and central thickness had not been achieved full recovery until 1 month after discontinuation. Conclusions: Recovery of after longterm use of OK lens is rapid for refractive change, but slow for corneal curvature and central thickness that to refit the contact lenses, practitioners need patience.