Visualization of the scleral structure changes at various stages of eyes with myopic maculopathy using polarization-sensitive OCT

Abstract

Purpose: To observe the detailed structures of the inner and outer sclera at various stages of myopic maculopathy using polarization-sensitive optical coherence tomography (PS-OCT).

Methods: A PS-OCT system was developed for imaging the posterior eye using a swept laser. Data from highly myopic patients who underwent PS-OCT examination between May and June 2019 were used to generate birefringence images (showing scleral fiber density), optic axis images (visualizing the orientation of scleral fibers), and streamline images (providing 3D reconstructions to visualize scleral fiber stream).

Results: A total of 89 eyes of 65 patients with high myopia were examined and analyzed for this study. The mean axial length was 30.4 ± 1.8 mm. In highly myopic eyes with a thin choroid, PS-OCT visualized the detailed structure of the sclera, and the optic axis images differentiated the direction of the inner and outer scleral fibers. In the optic axis and streamline images, the inner layer of the sclera contained radial fibers extending from the optic disc. In contrast, the outer layer of the sclera contained vertical fibers. With the progression of myopia, highly birefringent fibers first disappear in the inner scleral layer, followed by thinning of the inner layer itself. Subsequently, in the outer scleral layer, the number of highly birefringent fibers decreased. As myopic maculopathy worsened, the inner and outer layers of the sclera disintegrated.

Conclusions: PS-OCT is useful for observing the structures of the inner and outer sclera in various conditions of myopic maculopathy.

Keywords: Myopia; Myopic maculopathy; Optical coherence tomography; Pathologic myopia; Polarization-sensitive optical coherence tomography; Sclera.