Optic disc topography in patients with low-tension and primary open angle glaucoma.

Computerized optic disc topographic measurements (cup-disc ratio, neuroretinal rim area, disc volume) and automated visual field parameters (total field loss, mean sensitivity) were similar in 48 eyes with primary open angle glaucoma and 27 eyes with low-tension glaucoma. In open angle glaucoma, the neuroretinal rim area was negatively correlated with the cup-disc ratio and the disc volume. Total field loss was positively correlated with the cup-disc ratio and the disc volume and negatively correlated with the neuroretinal rim area. Eyes with low-tension glaucoma showed a negative correlation between neuroretinal rim area and cup-disc ratio, and between total field loss and rim area. However, low-tension glaucomatous eyes did not have significant correlations between disc volume and rim area and between total field loss and cup-disc ratio or disc volume. Cupping in low-tension glaucoma was broadly sloping, resulting in less disc volume alteration.