Electro-oculography as a functional test in pathological conditions of the fundus. II. Base-value and drop during dark adaptation.

IN our first paper (Fran9ois, Verriest, and De Rouck, 1955) we reported upon the modifications of the normal human electro-oculogram (EOG) by light adaptation (2,000 asb for 5 min.) and subsequent dark adaptation; if the former generally gives only a slight decrease in the initial value, the latter is constantly characterized by an initial increase in the recorded deflections (for 1 to 3 min.), followed by a large decrease which lasts about 10 min.; this drop is followed by a slight new increase. In a second contribution (Fran9ois and others, 1956) we studied an arbitrary and standardized base-value M in normal and pathological cases, and recognized that this value was often too low in cases of microphthalmia, primary pigmentary degeneration, cicatricial chorio-retinitis, and retinal detachment. As a third step in the physio-pathological study of the electrical standing potential of the eye, we now refer principally to the drop in the EOG during dark adaptation in pathological cases as compared with normal cases and with the base-values.