Abnormal visual electrophysiology Abnormal electrooculogram UMLS:C0159104 Abnormal EOG SNOMEDCT_US:442770004 The clinical electro-oculogram (EOG) is an electrophysiological test of function of the outer retina and retinal pigment epithelium (RPE) in which changes in electrical potential across the RPE are recorded during successive periods of dark and light adaptation.