Does Past Myopia Progression Predict Future Progression?

PURPOSE. To quantify the value of using prior changes in spherical equivalent refractive error (SER) and axial length (AL) to predict future myopia progression. METHODS. For this post hoc analysis of a randomized controlled trial, we used data from children ages 5 to 12 years with SER −1.00 to −6.00 D who had been randomized 2:1 to 0.01% atropine or placebo eye drops for 24 months. Multivariable linear regression evaluated the association of baseline-to-12-month change in SER and AL versus 12-to-24-month change while controlling for age and SER or AL at 12 months. Treatment groups were pooled for analyses; sensitivity analyses were conducted using only the placebo group. RESULTS. Among 187 children, 136 (73%) with complete data were included. For predicting a 0.50-D-or-more SER increase of myopia in the second 12 months based on observing a 0.50-D-or-more increase of myopia in the first 12 months, the positive predictive value was 42% (19 of 45; 95% confidence interval [CI], 29%–57%). Greater baseline-to-12-month SER change was weakly associated with greater 12-to-24-month SER change (0.20 D per additional 1.00 D; 95% CI, 0.02 to 0.39; P = 0.03; partial R² = 0.03). The 95% prediction interval half-width for 12-to-24-month change was ±0.66 D with prior change versus ±0.67 D without (difference = 0.01 D; 95% CI, −0.05 to 0.07). Analyses of AL and sensitivity analyses limited to the placebo group were qualitatively similar. CONCLUSIONS. Changes in SER and AL of children in the prior 12 months were poor predictors of future myopia progression, limiting their usefulness for clinical decision-making or selecting participants for clinical trials.