Optic Nerve Head Appearance in Chronic Primary Angle-Closure Glaucoma and Primary Open-Angle Glaucoma

Purpose: To evaluate the morphologic characteristics of the optic nerve head in chronic primary angle-closure glaucoma (CPACG) and primary open-angle glaucoma (POAG). Methods: The study included 77 normal subjects, 82 patients with CPACG, and 120 patients with POAG. Age and refraction in the POAG and normal control groups were matched to those of the CPACG group. Using color optic disc photographs, the presence or absence of qualitative signs for differentiating between normal and glaucoma eyes were recorded. Results: A rim notch was observed in 9 eyes (11.0%) in the CPACG group and in 27 eyes (22.5%) in the POAG group (P=0.04). Disc hemorrhage was found in 4 eyes (3.3%) in the POAG group and was not found in the CPACG group (P=0.15). Neither groups varied significantly in frequency of rim shape alteration (alteration of ISN`T rule), thinnest rim width outside the temporal sector, baring of the circumlinear vessel, bayonetting of vessel, nasalization of vessel, abnormally large peripapillary atrophy, abnormal form of peripapillary atrophy, or zone beta. Conclusions: Compared with the CPACG group, rim notches and disc hemorrhages were found more often in the POAG group. These results suggest that CPACG and POAG have at least partially different pathogenesis.