Effects of wearing orthokeratology lenses for more than 5 years on the ocular surface of adolescents.

Purpose: To evaluate the effects of long-term orthokeratology (OK) lens wear on the ocular surface in adolescents.

Methods: This cross-sectional case-control study included 30 adolescents who had worn OK lenses for more than 5 years and 30 demographically matched adolescents who wore spectacles. They were allocated to the experimental and control groups, respectively. The ocular surface condition, visual acuity, corneal fluorescein staining, tear meniscus height, non-invasive tear break-up time, tear film lipid layer characteristics, and upper and lower meibomian glands were assessed for all participants.

Results: The adolescents who wore OK lenses for more than 5 years had lower average non-invasive tear break-up time (t = 2.099, p = 0.04), thinner tear film lipid layers (z = -2.657, p = 0.008), and higher rate of lower meibomian gland loss (MGL) (t = -5.541, p＜0.001) than those in the control group. Sex and refraction were independent predictors of lower MGL among long-term OK lens wearers. Males had a higher MGL rate than females (B = 16.308, 95 % confidence interval [CI]: 6.05, 26.56; p = 0.003). For every 1-diopter (D) increase in refraction (1D reduction in myopia), lower MGL decreased by 4.044 % (B = -4.044, 95 % CI: -8.00, -0.09; p = 0.045).

Conclusions: Long-term OK lens wear by adolescents is associated with increased lower MGL and reduced tear film stability. Male sex and high myopia are risk factors for MGL. Regular follow-up and close monitoring of ocular surface health are recommended during extended OK lens use.