AIM:To evaluate the safety and effectiveness of Orthokeratology in correcting and curing mild and moderate myopia for teenager patients by investigating the clinical response of wearing Orthokeratology at day or night and further analyze the underlying factors.

METHODS: Eighty-nine eyes(spherical equivalent refraction≤-6.00D, astigmatism with the rule ≤-1.50D and astigmatism against the rule ≤-0.75D)of 45 teenagers aged between nine and twenty wearing Orthokeratology contact lens from 2012 to 2014 were selected and then randomly divided into two groups, twenty-nine eyes wearing at day and sixty eyes wearing at night. The lens were put on eight to ten hours each time. Uncorrected visual acuity, residual spherical equivalent refraction, central corneal thickness, corneal curvature were examined punctually in addition to checking any kind of eye damage or complication after Orthokeratology at 1wk, 1, 3 and 6mo.

RESULTS:Uncorrected visual acuity was markedly corrected while residual spherical equivalent refraction was reduced after one wk contact lens wearing treatment. The above results were of statistical significance(P<0.01). Notably corneal curvature became more flattened after one wk, and the average K value got decreased from 42.28±1.13D to 40.79±1.26D(wearing at day)and 42.18±1.03D to 40.35±0.99D(wearing at night)respectively. The corneal curvature results had a statistically significant difference comparing one wk after wearing Orthokeratology than before(P<0.05), but there was no such difference comparing one wk with one, three or six mo(P>0.05). Central corneal thickness at one mo had the most obvious change which decreased 7.26±1.38μm(wearing at day)and 15.15±0.50μm(wearing at night)respectively, showing great statistical significance(P<0.01). The positive cases of corneal epithelium dyeing after orthokeratology were nine(wearing at day)and twenty-eight(wearing at night), which correspondingly accounted for 31% and 47%.

CONCLUSION: Orthokeratology can effectively reduce myopic diopter and improve uncorrected visual acuity. However, we still can not neglect the risk and should make sure of the safety by standardizing the optometry process and improving the fitting skills.