Longitudinal Border Tissue Configuration Changes during Experimental High Myopia Development in Juvenile Tree Shrews

Abstract

Purpose : To investigate the border tissue (BT) configuration changes during experimental high myopia development in juvenile tree shrews.

Methods : Juvenile tree shrews were randomly assigned to two groups: binocular normal visual experience (n=18) and monocular -10D lens treatment to induce experimental high myopia (n=12) in one eye while the other eye served as control. Refractive and biometric measurements were obtained daily. Forty-eight radial optical coherence tomography B-scans through the center of the optic nerve head (ONH) were obtained weekly for six weeks. Anterior scleral canal opening (ASCO) and Bruch’s membrane opening (BMO) were manually segmented after nonlinear distortion correction of each B-scan. BT configurations were labelled as internally or externally oblique if the BMO position was more than 3 µm inside or outside the ASCO perimeter, respectively. Differences among groups were assessed using linear mixed models with a Bonferroni correction to maintain an appropriate Type I error rate.

Results : BT configuration showed significant group interaction with time (P<0.001), where the prevalence of internally oblique configuration gradually increased while the prevalence of externally oblique configuration gradually decreased in experimental high myopic eyes compared to both normal (P<0.0001) and control (P<0.0001) eyes (Figure 1). A significantly higher tendency of change from internally to externally oblique configuration was observed in the experimental high myopic eyes in four sectors: Nasal, Inferonasal, Inferior and Inferotemporal (P <0.005) (Figure 2).

Conclusions : Experimental high myopia leads to an asymmetric remodeling of the ONH tissues, where the BT configuration changes from internally to externally oblique in ONH sectors that are closest to the posterior pole (nasal in tree shrew). This asymmetric ONH remodeling during high myopia development may contribute to the increased risk of glaucoma later in life.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.