Electroretinograms from noncorneal electrodes.

A. lthough it has long been known that retinal action currents are present, the electroretinogram (ERG) has not become the subject of detailed investigation in the human until recent years. Before Riggs demonstrated that the response might be easily recorded from an electrode supported by a contact lens, no satisfactory method for continuous recording from the human was available. This technique has greatly facilitated research, but use of a contact lens electrode limits the maximum length of experimental session possible and may, in some cases, restrict the properties of the visual task to be observed and measured. In addition, not all individuals find the lens to be comfortable, and this may also increase recording difficulty. Motokawa and Mita reported that the ERG could be recorded from a pair of noncorneal electrodes, one attached to the bridge of the nose and the other attached to the temple near the eye being investigated. This method has not been widely used since the small signals it provides are usually well masked by bioelectric artifacts. The present report shows that ERG's