The effect of orthokeratology is completely reversible or not and its myopia control effect on adolescent

Abstract

Objective Investigating whether the effect of long-term wearing orthokeratology on cornea is completely reversible or not and its myopia control effect. Methods This was a prospective cohort study. Fifty-five adolescent (110 eyes) wearing orthokeratology and 55 adolescent (110 eyes) wearing full correction single vision(SV) spectacles were collected. After 2 years' wearing, orthokeratology group stop wearing at least 30 days before re-examination. Spherical equivalent (SE) and axial length(AL) of SV spectacles group were tested before trial and 2 years later. SE, AL, astigmatism, SimK, corneal horizontal and vertical refractive power (corneal k value), uncorrected visual acuity(UCVA), etc. were recorded in orthokeratology group before trial and 2 years later. Data were analyzed using paired and independent t test, repeated measurement ANOVA, and Pearson correlation regression analysis. Results Forty-six cases (92 eyes) and 43 cases (86 eyes) finished the trial in SV and orthokeratology group, respectively. Two years later, SE and axial length increased -1.68±0.84 D, 0.59±0.48 mm in SV spectacles group and -0.80±1.04 D, 0.37±0.34 mm in orthokeratology group, respectively, there were significant difference between the two groups (t= 25.81, 20.13, P<0.01). For orthokeratology group, there are some increase in astigmatism and SimK, 0.30 ± 0.24 D and 0.28 ± 0.22 D respectively (t=5.83, 5.45, P<0.05), in corneal horizontal refractive power reducted (0.31 ± 0.18 D, t=7.43, P<0.05). There was a significant difference in UCVA at different time points before and after wearing orthokeratology, and the UCVA was significantly improved after wearing orthokeratology (F=250.80, P<0.01). Conclusion Wearing orthokeratology could significantly improve the UCVA of myopia patients, and control the progression of adolescent myopia. But Long-term wearing may result in slight increase in astigmatism, slight reduction in corneal horizontal K, this indicates that the effect of orthokeratology may not be completely reversible. Key words: Orthokeratology; Myopia; Reversible; Corneal refractive power