An Evaluation of the Photopic Electroretinogram Using Lower Eyelid Electrodes
Interim rept. Jan 1988-Jan 1990,
SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TX
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The use of corneal contact lens electrodes for recording Electroretinograms ERG is difficult in some patients children and impossible in others hyperbaric patients due to unusual recording conditions. After reviewing the various published methods already tested, we implemented a technique that employs a lower eyelid electrode. In addition, a Ping-Pong ball Ganzfeld was fabricated to mimic the Ganzfeld dome typically used in clinical laboratories. Three questions were then addressed 1 the adequacy of the method for acquiring photopic ERGs 2 the influence of the direction of gaze on ERG parameters 3 the day-to-day reliability of the method. When ERGs derived from contact lens electrodes were compared with those obtained from lower eyelid electrodes under the same test conditions, it was found that the lower eyelid electrode waveforms were smaller in amplitude but identical in shape to wave forms produced by corneal contact lens electrodes.