The Impact of Myopia Control Spectacle Lens Designs on Visual Function

PURPOSE: To profile the immediate effect of defocus-modulating and contrast-modulating myopia control spectacle lens interventions on visual function. METHODS: Healthy myopic (mean spherical equivalent (MSE) -4.25 to -0.50 D) young adults, corrected with contact lenses, wore diffusion optics technology (DOT), defocus incorporated multiple segments (DIMS), highly aspherical lenslets (HAL) and standard single vision (SV) plano trial spectacle lenses, in a prospective, single-visit, double-blind, four-way randomised crossover study. Distance and near high- and low-contrast visual acuity (VA), contrast sensitivity, reading performance, accommodative facility, visual search task and accommodative accuracy were assessed foveally through the central zone (CZ) and/or peripheral zone (PZ) of the lenses. RESULTS: Twenty participants (16 female) were recruited, with a mean (±SD) age of 22.4 (±2.72) years and MSE -2.21 (±1.10) D. VAs through the PZ differed significantly between myopia control lenses and SV, with the HAL and DIMS exhibiting lower VA across all testing conditions (all p <0.05) and DOT demonstrating equivalence to SV with high contrast letters. Contrast sensitivity was similarly reduced for all lenses through the CZ, while HAL and DIMS performed worse than both SV and DOT through the PZ (p <0.01). Near acuity threshold, reading speed and critical print size through the PZ were comparable for SV, DOT and HAL (all p >0.05), whereas DIMS exhibited worse near acuity threshold and critical print size (p <0.001). No significant differences emerged for error score (p = 0.53), accommodative facility refocusing cycles (all p >0.05) or visual search duration (CZ: p = 0.68; PZ: p = 0.35). Accommodative response was similar across lenses (all p >0.05); however, SV had lower variability at distance through the PZ than DOT, HAL and DIMS (p <0.001). CONCLUSION: All three myopia control lenses exhibited visual performance comparable to standard SV lenses through the CZ. Clinicians should note differences in visual performance, especially VA and reading speed through the lens periphery and their relative testing.