The electro-oculogram in eyes with choroidal melanoma.

The electro-oculogram (EOG) in the involved eyes of 20 patients with a choroidal melanoma was compared to the EOG in the uninvolved eyes of these 20 patients and to the EOG in both eyes of 10 patients with a choroidal nevus in one eye and 19 normal control patients. A statistically significant reduction in the EOG occurred in eyes with melanomas compared to patients with nevi. No difference was found between the EOG of normals and the uninvolved eye of melanoma patients. Patients with nevi did not differ from normals. This observation was independent of tumor size and was not related to the extent of retinal detachment.