Pattern electroretinogram: use of noncorneal skin electrodes.

Pattern electroretinograms (ERGs) were recorded in three adults by a noncorneal electrode technique: silver-silver chloride skin electrodes attached to the inferior orbit of the left eye while the subject monocularly viewed a high contrast checker-board that reversed in contrast at a rate of 10 Hz. Recordings revealed pattern ERGs with an average amplitude of 1.5 microV. In addition, pattern ERGs were recorded as a function of spatial frequency and contrast of a square-wave grating. The results showed that an increase in spatial frequency or contrast yielded an increase in the amplitude of the pattern ERG. The results demonstrate that the pattern ERG can be recorded with a noncorneal electrode technique and that the noncorneal electrode technique is sensitive to changes in retinal function. Finally, it is demonstrated that the pattern ERG can transfer between the eyes such that the pattern ERG from a viewing eye can be recorded from an electrode placed below an occluded eye.