Objective: To find the optic disc features of asymmetric primary open-angle glaucoma.

Methods: In this observational case-control study, 52 consecutive open-angle glaucoma patients with unilateral visual field defects participated. In each patient, an optic disc analysis using Heidelberg Retina Tomography III (HRT-III) was performed. Optic disc parameters of HRT-III of eyes with abnormal visual fields were compared with their fellow eyes with normal visual fields.

Results: The optic disc area of the eyes with abnormal visual fields (2.35 +/- 0.55 mm(2)) was larger than that of the fellow eyes with normal visual fields (2.25 +/- 0.43 mm(2)) (P = 0.03). Of the eyes with abnormal visual fields, 63.5% had a larger optic disc area than their fellow eyes with normal visual fields. In addition, in the eyes with abnormal visual fields, the cup areas were larger (P = 0.000001-0.02), whereas the rim and retinal nerve fiber layer thicknesses were thinner (P = 0.000002-0.036) than those of the fellow eyes with normal visual fields.

Conclusions: The optic disc area of eyes with abnormal visual fields was larger than that of their fellow eyes with normal visual fields, suggesting that Chinese open-angle glaucoma patients with larger optic discs might be susceptible to glaucomatous optic damage.