Spectacle lenses with slightly aspherical lenslets for myopia control: clinical trial design and baseline data

Objectives Myopia is a major public health problem and it is essential to find safe and effective means to control its progression. The study design and baseline data are presented for a one-year prospective, double-masked, crossover, randomized clinical trial evaluating the efficacy of single vision spectacle lenses with concentric rings of slightly aspherical contiguous lenslets technology (SAL) on myopia control. Methods One hundred 8- to 13-year old Chinese children with a refractive error of -0.75 D to -4.75 D were assigned to two groups. In Group 1, SAL and single vision lenses were each worn for 6 months, and Group 2 wore the lenses in the reversed order. Primary outcomes are axial length and spherical equivalent of cycloplegic refractive error. Secondary outcomes included corneal thickness, anterior chamber depth, lens thickness, visual acuity, and lens adaptation. Results No significant differences in baseline parameters (cycloplegic spherical equivalent, axial length, age) were found between groups (0.49 < p < 0.94). All children adapted well to the test lenses and there was no significant difference in visual acuity between the SAL and single vision lenses (p = 0.27). Conclusions The children in the two well balanced groups had comparable visual acuity and adapted well to the test lenses. These results imply that visual acuity can be well improved by SAL lenses. Clear visual acuity provides the assurance for good compliance in this longitudinal study. Keywords: Myopia, Spectacle lenses, Prospective studies, Refractive errors, Axial length