Semi-automated evaluation of trabecular meshwork and schlemm canal imaged with OCT in children with normal eyes vs. primary congenital glaucoma

Maldevelopment of Schlemm canal (SC) and trabecular meshwork (TM) is proposed in the pathogenesis of primary congenital glaucoma (PCG). This study aims to evaluate a semi-automated segmentation algorithm of SC and TM in pediatric patients scanned using overhead-mounted optical coherence tomography (OCT). Twenty-four children (33 eyes: 17 PCG, 16 normal), with mean age 1.3 ± 1.08 years, had anterior segment OCT imaging. Manual segmentation of SC and TM on individual B-scans represented the gold standard and was compared to semi-automated segmentation of the same structures. Intraclass correlation (ICC) compared the manual and semi-automated algorithm for several parameters: SC area (0.940), circularity (0.742), and aspect ratio (0.861); and TM thickness (0.807). Comparing eyes with PCG vs. normal, we found: (1) decreased SC area (4084 ± 4553µm² vs. 7362 ± 3961µm², p = 0.008), (2) increased SC circularity (0.46 ± 0.15 vs. 0.36 ± 0.14, p = 0.011, 3) increased TM thickness (152 ± 43 μm vs. 110 ± 27 μm, p < 0.001) and 4) decreased SC aspect ratio (5.35 ± 2.51 vs. 7.06 ± 2.48, p = 0.012) in eyes with PCG. Semi-automated segmentation permits assessment of differences in SC and TM morphology in normal vs. PCG eyes. Further work is necessary to understand how SC and TM differ in these patients as well as other forms of childhood glaucoma.