Slowing myopia progression with a novel spectacle lens - 1-year, randomized double-masked, cross-over clinical trial.
PURPOSE To evaluate the effectiveness of test spectacle lens in slowing myopia progression as compared to single vision (SV) spectacle (SPL). DESIGN Cross-over trial. SUBJECTS 120 children aged 6-12yrs, cycloplegic spherical equivalent (SE) of -0.75D to -5.00D. INTERVENTION Enrolled participants were randomly assigned to wear either SV or test SPL (n = 60 each group). The test SPL incorporates a central clear zone and four annular cylindrical rings in the paracentral zone with a mean surface power of +4.00D. For first six months (stage I), children wore their assigned lenses and then crossed over to wear the other lens for the second six months (stage II). OUTCOMES Six- monthly changes in SE and AL from baseline presented as mean and 95% confidence intervals (CIs). Differences between groups were assessed using multiple linear regression, adjusting for confounders. To determine potential rebound effect, progression with SV during stage II was compared to progression with SV in stage I. RESULTS Myopia progression was significantly slower with test SPL during both stages. During stage I, the difference in progression (Δ) between test SPL and SV were 0.32D (0.21, 0.43) and 0.12mm (0.09，0.16) (P < 0.001). During stage II, myopia progressed slower by 0.25D (0.15, 0.36) and 0.11mm (0.07, 0.14) (P < 0.001) with test SPL. Progression with SV during stage I and stage II did not differ significantly (SE: -0.42 ±0.31D vs -0.51± 0.30D, p=0.119; AL: 0.19 ±0.11mm vs 0.22± 011mm, P = 0.182). CONCLUSIONS Test spectacles significantly slow myopia in majority of eyes in 6 months and no statistically significant rebound signal was detected during the observation period.