To investigate changes in axial length in children undergoing orthokeratology (OK) and evaluate short-term axial change in predicting post-OK myopia progression.
In this retrospective study, the subjects included 70 myopic children aged 8 to 15 years wearing OK contact lenses for more than 3 years. Axial length changes at 0.5, 1, 2, and 3 years relative to the baseline were measured. Patients were evaluated for age, spherical equivalent refraction (SER), pupil size, and half-year axial change using repeated analysis of variance and multivariate linear regression analysis to predict half to 3 year-axial elongation (AE, seventh–36th month post-OK).
The axial length grew significantly during the 3 years; the mean annual axial growth was 0.20±0.12 mm. The half-year axial change was 0.04±0.12 mm. The univariate linear analyses showed that half to 3-year AE was correlated with baseline age (r=−0.393, P<0.001) and half-year axial change (r=0.379, P=0.001), but not pupil diameter (P=0.692) or SER (P=0.673). In a multiple linear regression model, the half to 3-year AE was related with the baseline age (standardized β=−0.312, P=0.007) and half-year axial change (standardized β=0.293, P=0.01). The model was fair (adjusted R2=0.21) and statistically significant (F=10.24, P<0.001).
It is practical to predict long-term AE with half-year axial change for children with OK correction. Therefore, this may aid in fast and timely measures in children who are predicted to have rapid myopia progression.