Pattern electroretinograms (PERGs) were recorded in ten subjects employing two varieties of electrodes: a gold foil electrode inserted into the lower fornix, and a gold cup skin electrode overlying the inferior orbit. Recordings were obtained as subjects viewed a checker-board pattern that reversed with a frequency of 2.1 Hz. Check size varied from 4 degrees to 0.25 degrees, at a contrast of 98%. Two additional recordings were obtained with 0.5 degree check size, lower luminance, and lower contrast. The PERG recorded with a skin electrode was similar in configuration to the PERG recorded with a gold foil electrode, but smaller in amplitude. The equation relating the amplitude of the b-wave recorded from the foil electrode (y) to the amplitude of the b-wave recorded from the skin electrode (x) was: y = 0.127 + 2.150x, with an R value of 0.82. Latencies of both the a- and b-waves were comparable under both recording conditions. We conclude PERGs may be adequately recorded with a noncorneal skin electrode. While the gold foil electrode offers larger amplitude waveforms, the skin electrode may be successfully substituted in those patients unable to tolerate corneal contact.
ASJC Scopus subject areas
- General Neuroscience