PUPILLARY AND VISUAL-FIELD EVALUATION IN PATIENTS WITH MELANOCYTOMA OF THE OPTIC DISK

Patients (20) with melanocytoma of the optic disc underwent Goldmann perimetry and pupillary evaluation. Two patients (10%) had normal visual fields. Minimal blind spot enlargement was found in 3 (15%). Patients (15) (75%) had a greatly enlarged blind spot, of which 10 had concomitant nerve fiber bundle field defects. These consisted of a nasal step in 2 cases (10%), relative nerve fiber bundle defects in 4 cases (20%) and an absolute arcuate defect in 4 cases (20%). The blind spot enlargement relates to the pigmented tumor extending beyond the disc boundary, thereby shading the peripapillary retina. The nerve fiber bundle defects result from injury to the visual axons passing through the nerve head, although the mechanism is uncertain. A Marcus Gunn pupillary sign produced by the melanocytoma was found in 6 patients (30%), all of whom had a substantial relative or absolute nerve fiber bundle defect.