Abstract
Purpose :
Short-term modulation of choroidal thickness may be an indicator of long-term myopia control. A previous study showed that the choroid thickens to full field spectacle lens myopic defocus, and more so in the evening than morning. Multifocal soft contact lens that provide peripheral myopic defocus have been shown to be effective in myopia control. The goals of this study were to assess short-term effects of full field or peripheral myopic defocus on choroidal thickness and to investigate time-of-day effects in young adults.
Methods :
Healthy young adults (n=10) ages 28.2 ± 3.19 years participated in four sessions, separated by 1 to 4 days, two in the morning (9am) and two in the evening (5pm). For each session, participants first watched a movie for 10 min in a large screen at 2 m with single vision distance corrected contact lenses (+0.5 D for the working distance), and choroidal thickness was measured using optical coherence tomography(OCT) in both eyes. Then, the experimental lens, which provided an additional +2.5D full field or peripheral field defocus was placed on the left eye, and the participant continued to watch for 60 minutes. OCT was repeated. The distance-correction was replaced and recovery was measured after 20 minutes. Choroidal thickness change was determined for control and experimental eyes, and the difference between eyes was calculated. Repeated measures ANOVA with post-hoc Bonferroni correction was used to assess changes in choroidal thickness.
Results :
Baseline choroidal thickness was similar in the morning (320.3±25.7 μm) and evening (335.6±26.6 μm, P=.4) and was similar between right and left eyes (P=.2). Following 60 min exposure to full field myopic defocus, the choroid of the experimental significantly thickened relative to the control eye in the morning (7.9±2.4 μm, P=.03), but not in the evening (6.0±2.7 μm, P=.15). Following 60 minutes exposure to peripheral field myopic defocus, the choroid did not significant change in the morning or evening (P=1 for both).
Conclusions :
Findings show that short-term exposure to full field contact lens induced myopic defocus leads to significant thickening in the morning, but not in the evening. Peripheral field contact lens induced myopic defocus did not induce choroidal thickness changes. Future analysis including a larger sample size may be able to better distinguish small changes in choroidal thickness using OCT imaging.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.