In normal eyes, the optic disc size shows a high interindividual variability. In the diseased eye, some optic nerve anomalies and diseases occur preferentially in small optic discs, and some are more common in large optic nerve heads. We conducted a study to determine whether glaucoma subtypes are correlated with the optic disc size or not. Stereo optic disc photographs of 997 eyes with primary open-angle glaucoma, 44 eyes with normal-tension glaucoma, 129 eyes with pseudoexfoliative glaucoma, and 850 normal eyes were examined. Compared to eyes with primary open-angle glaucoma (mean optic disc area: 2.63 +/- 0.61 mm2), the optic disc was significantly larger in eyes with normal-tension glaucoma (2.96 +/- 0.73 mm2; P < 0.05), and it was smaller but not significantly smaller in eyes with pseudoexfoliative glaucoma (2.53 +/- 0.51 mm2). Eyes with primary open-angle glaucoma and normal eyes (2.69 +/- 0.69 mm2) did not differ significantly in optic disc size. The abnormally large optic disc in eyes with normal-tension glaucoma may be important diagnostically and pathogenetically.