Abstract
Purpose :
In a previous work (KhalafAllah MT, et al. IOVS 2022;63: ARVO E-Abstract: 3814), experimental high myopia was shown to induce profound thinning of peripapillary choroid-retinal pigment epithelium complex (choroid/RPE) and sclera during the first week of myopia development followed by a stable phase until 59 days of visual experience (DVE). In this study, we aimed to investigate the impact of sustained lens treatment on peripapillary chorioscleral remodeling until young adulthood.
Methods :
Juvenile tree shrews were randomly assigned to two groups: normal visual experience (n=18 eyes, 9 animals) or binocular -10D lens treatment to induce high myopia (n= 22 eyes, 11 animals). Lens treatment started at 24 DVE and was sustained for 5 months. Refractive and biometric measurements were obtained every 3 days. Optical coherence tomography of the optic nerve head (Spectralis, Heidelberg Engineering) was performed weekly. Thickness values were quantified over a 50-µm band starting at 1000 µm from anterior scleral canal opening centroid. A linear-mixed-effects model with a random intercept and slope was employed to test for time-group interaction differences among groups.
Results :
Lens-treated eyes developed high levels of myopia and significant axial elongation compared to normal eyes (P<0.001). Most lens-treated animals developed and maintained a refraction (-10.6±1.9 D) close to the power of the lens (-10D) until young adulthood. Unexpectedly, 2 animals developed significantly higher levels of myopic refraction (-18.2±2.9 D) and axial elongation in both eyes compared to animals with non-progressive myopia (P<0.001). Compared to non-progressive eyes, progressive eyes showed significantly greater thinning of the choroid/RPE during the first week of myopia development (Phase I, Figure 1) followed by a stable phase until 59 DVE (Phase II) and subsequently by significantly greater scleral thinning until young adulthood (Phase III).
Conclusions :
Sustained negative lens treatment can lead to progressive myopia development in tree shrews. Profound choroidal thinning during early myopia development can serve as a potential biomarker of future scleral thinning, axial elongation, and myopia progression.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.