Polarization-Sensitive Optical Coherence Tomography Imaging of Posterior Staphyloma Edges in Eyes With High Myopia.

Purpose: To investigate the arrangement and orientation of the collagen fibers in the inner and outer scleral layers at the edges of posterior staphylomas using polarization-sensitive optical coherence tomography (PS-OCT). Methods: This observational case series study enrolled 105 patients with high myopia (refractive error <-6.0 diopters or axial length ≥26.5 mm) who underwent PS-OCT examinations between August 2023 and May 2024 at the Institute of Science Tokyo. Posterior staphyloma was diagnosed in 88 eyes of 60 patients using ultra-widefield OCT, followed by PS-OCT image processing. Thirty-six eyes from 27 patients with clearly identifiable staphyloma edges were included for final analysis. PS-OCT images were analyzed to assess the scleral fiber orientation and birefringence at the staphyloma edges, including macular and inferior types. Results: Optic axis images showed that 25 (18 upper and 7 lower) of 30 (83.3%) macular staphyloma edges had an aggregation of the inner scleral fibers, characterized by an arc-like gathering of the horizontal fibers along the edge. All eight upper edges of the eight eyes with an inferior staphyloma had an aggregation of the inner scleral fibers with relatively linear horizontal fibers across the macula. Birefringence images of the upper and lower edges of the macular and inferior staphylomas had different patterns, including a mixture of low and high, and relatively high birefringence. Conclusions: An uneven aggregation of inner scleral fibers at the staphyloma edges in highly myopic eyes offers novel insights into staphyloma pathogenesis. This finding also holds pivotal implications for developing targeted interventions to prevent the progression of staphylomas in high myopia.