Part-time Versus Full-time Spectacles for Myopia Control (ParMA Study): A Randomized Clinical Trial.

Introduction To compare myopia progression in school-aged children of Caucasian origin wearing part-time vs. full-time full correction with single-vision spectacles. Methods This prospective, randomized controlled trial included 30 children with bilateral myopia, who received either full-time or part-time treatment with single-vision spectacle lenses. Myopia progression was assessed as the mean change in cycloplegic spherical equivalent refraction (SE), mean change in axial length (AL), and mean change in sub-foveal choroidal thickness (SChT), over a 12-month follow-up period. Results A total of 32 eyes were treated with part-time single-vision spectacles (intervention group) and 28 eyes with full-time single-vision spectacles (control group), respectively. The part-time treated group reported no spectacle use during near-work activities for a mean of 6.2 hours/day. At the 12-month assessment, there was no significant difference between part-time and full-time correction groups in mean SE change (MD: -0.05 D, 95% CI: -0.50 - 0.39 D; 0.81), in mean AL change (MD: -0.07 mm; 95% CI: -0.20 - 0.06 mm; P 0.30), and in mean SChT change (MD: -11.45 μm; 95% CI -22.60 - 14.16 μm; P 0.67). Conclusion Myopia progression in Caucasian children treated with part-time, single-vision spectacle use was not different compared to full-time, single-vision spectacle use, over a 12-month follow-up period.