The anterior scleral thickness in eyes with primary open-angle glaucoma

Purpose To investigate the anterior scleral thickness (AST) and its associations with Schlemm's canal (SC) area, trabecular meshwork (TM) thickness and length, and scleral spur (SS) length in healthy and primary open-angle glaucoma (POAG) groups. Methods Thirty-five eyes of 35 healthy subjects and 23 eyes of 23 patients with POAG were included. The AST, SC area, TM thickness and length, and SS length were measured using swept-source optical coherence tomography. AST was measured at 0 mm (AST0), 1 mm (AST1), 2 mm (AST2), and 3 mm (AST3) from SS. Associations between AST and SC area, TM thickness and length, and SS length were also estimated. Results AST0 (728.84 +/- 99.33 vs. 657.39 +/- 67.02 mu m, p < 0.001), AST1 (537.79 +/- 79.55 vs. 506.83 +/- 57.37 mu m, p = 0.038), AST3 (571.09 +/- 79.15 vs. 532.13 +/- 59.84 mu m, p = 0.009), SC area (6304.26 +/- 1238.72 vs. 4755.64 +/- 1122.71 mu m(2), p < 0.001), TM thickness (107.21 +/- 31.26 vs. 94.51 +/- 24.18 mu m, p = 0.035), TM length (736.20 +/- 141.85 vs. 656.43 +/- 127.03 mu m, p = 0.004), and SS length (219.89 +/- 50.29 vs. 174.54 +/- 35.58 mu m, p < 0.001) were significantly greater in healthy group than in POAG group. In addition, SC area, TM thickness, and SS length were significantly and positively associated with AST0 in the healthy group, whereas no similar associations were observed in the POAG group. Conclusions Compared with the healthy group, AST was significantly thinner in the POAG group, which also had smaller SC and TM dimensions. Moreover, the SC area, TM thickness, and SS length were significantly and positively associated with AST in the healthy group. Thus, AST might play an important role in maintaining TM and SC morphology and further in the pathogenesis of POAG.