The Influence of Highly Aspherical Lenslets on Choroidal Thickness and Axial Length

Objectives: Recent studies have shown that highly aspheric lenslets (HAL) are effective in slowing myopia progression. Moreover, research indicates that an enhancement in choroidal thickness might serve as a biomarker for evaluating the efficacy of myopia control treatments. Therefore, this study examined the short-term effects of HAL and full-field +3.00 diopters (D) myopic defocus on sub-foveal choroidal thickness (SFCHR). Design: Prospective experimental study. Participants: Twenty-five participants aged 20-30 (mean 24.56 ± 2.467) years with a refraction error of emmetropia to -5.0 D (mean -2.255 ± 1.514 D). The contralateral non-dominant eye was used as control for each participant. Methods: The participants watched a movie projected at 6 m for 90 min on two separate occasions while wearing HAL or +3 D full-field myopic defocus lenses on their dominant eye. The control eye wore only a single-vision contact lens with the best-corrected distance vision. Three measurements of AL and SFCHR were captured before defocus, and after 60 and 90 min of defocus for both eyes. The main outcome measures were changes in SFCHR and AL over time. Results: Exposure to HAL and +3 D myopic defocus significantly increased SFCHR in the defocused eyes compared to the baseline (p < 0.001). The increase in SFCHR was 6.62 ± 6.32 µm with the HAL intervention and 7.36 ± 8.83 µm with the +3 D intervention. The difference between the two interventions was not statistically significant (p = 0.595). A significant mean difference of 3.176 ± 1.318 µm in SFCHR increase was observed with +3.00 D full-field defocus in the defocused eyes compared to the control eyes over the measurement period (p = 0.020). Conclusions: Short-term exposure to full-field myopic defocus increased choroidal thickness, which was comparable with that observed in peripheral myopic defocus with HAL, although the effect appears less pronounced.