Changes in the Electroretinogram c-Wave Following Laser Insult.

Abstract : The study was conducted to compare changes in the electroretinogram c-wave following ruby laser insult with the threshold for ophthalmoscopically visible lesions. Dark adapted, pigmented rabbits were used as experimental subjects. A corneal ring electrode was used to monitor the electroretinogram. The experimental procedure included recording the pre-burn responses which were evoked by a 27.5 micro J argon stimulus, exposing the retina to ruby laser radiation, and recording the post burn responses at 30-minute intervals for one hour post insult. The data shows an increase in c-wave amplitude for ruby energies from approximately 75 percent to 300 percent of the ophthalmoscopic threshold. The amplitude decreased above 300 percent of threshold. The increases in c-wave amplitude are thought to be caused by increased transretinal potassium flux. The decreases in c-wave amplitude are caused by decreased potassium flux following pigment epithelial cell death. (Author)