Abstract
PURPOSE: Peripheral defocus and image contrast modulation are key strategies in myopia control, but both inherently reduce retinal image contrast. To date, no in vivo study has directly compared these effects. This study evaluated the contrast reduction profiles of different myopia control spectacles to better understand their underlying mechanisms. METHODS: Through-focus images (TFIs) were obtained with a double-pass instrument in a model eye and in human eyes wearing four spectacle designs: DIMS, Stellest, diffusion optics technology (DOT), and MyoCare. The naked eye served as a reference. Thirteen participants (mean age = 29.0 ± 3.5 years) were tested at the fovea and at 10° and 20° eccentricities in the temporal and superior fields. Lenses were decentered by 1.5 cm to assess off-axis effects. Model eye tests included only the central field. Retinal image contrast (RIC) was calculated as the coefficient of variation of pixel intensity in TFIs. RESULTS: In the model eye, RIC ranked from highest to lowest as follows: naked eye, DIMS, DOT, MyoCare, and Stellest. In vivo, DOT results were excluded due to a weak signal. A nonparametric test revealed significant differences in RIC among lenses at the fovea (P = 0.009) and at 10° in the temporal/superior fields (P = 0.05). Post hoc analysis showed that Stellest produced the greatest reduction in RIC, whereas MyoCare and DIMS demonstrated similar levels of contrast loss. CONCLUSIONS: All myopia control lenses reduced retinal image contrast, with Stellest inducing the strongest reduction. MyoCare and DIMS showed comparable effects. Lens-induced optics primarily influenced contrast in the near periphery, while ocular optics dominated at larger eccentricities.