Clinic effect and relevant influencing factors of overninght orthokeratology in myopic adolescent

Abstract

Objective To observe the clinical effect of overnight orthokeratology in the treatment of myopic adolescent, assess the changes in uncorrected visual acuity, refraction, corneal curvature, central corneal thickness and axial length during wearing orthokeratology, before and after 1 year of wear, and analyze factors influencing change of axial length. Methods Prospective clinic study of 56 subjects (age ranged from 7 to 16 years old, spherical refractive errors of the subjects ranged from-0.75--6.00D) who met the inclusion criteria were enrolled in this study and fit with orthokeratology. The changes in uncorrected visual acuity, refraction, corneal curvature and central corneal thickness were measured 1 month, 3 months, 6 months and 12 months after wearing orthokeratology. The uncorrected visual acuity, refraction, corneal curvature, central corneal thickness and axial length were also measured and compared with the baseline data after the discontinuation of lens wear for 1months when 12 months of follow-up study completed. Data were analyzed using repeated ANOVA and paired t test. Multiple linear regression analysis was performed to identify explanatory variables with a statistically significant contribution to axial elongation. Results Fifty-two subjects completed the 13-months follow-up study. At baseline, their mean age was 11.062 ±2.631 years old. The mean spherical equivalent refractive error was -3.565±1.330D. The uncorrected visual acuity, refraction, cor-neal curvature and central corneal thickness were statistically significant different during the 12-month period. The spherical refractive errors, spherical equivalent refractive errors and axial length after 12-month treatment statistically increased compared with data at baseline, while uncorrected visu-al acuity, cylinder refractive errors, corneal curvature and central corneal thickness did not. The axial elongation showed significant simple correlations with the baseline age of subjects (F =86.910, P< 0.01), the baseline age was negatively correlated with the change of axial length. Conclusions Orthokeratology can safely and effectively control the axial growth and retard the progression of myopia; the effect is significant and reversible, initial age is the main variables involved in influencing the control effect. Key words: Myopia; Orthokeratology; Refraction; Corneal curvature; Central corneal thickness; Axial length