Case Study #1 (Chris)

A young infant was referred Children's Hospital because he had nystagmus, did not look at his mother's face, and seemed to completely ignore all visual stimuli. He did not respond at all to the Teller Acuity cards, which are cards with simple gratings on them designed to test visual response. The question was, could he see at all? It was decided to measure his vision with the Visual Evoked Potential (VEP) test.

Chris had an acuity of about 6 cycles per degree - this is equivalent to about 20/100. This is in the normal acuity range for two-month old infants. He was then referred for an electroretinogram (ERG).

Chris's results on the VEP Chris's results on the VEP

It turned out that Chris had perfectly normal responses for his age on the ERG. The results are always calculated for age because the eyes change a great deal during the first few months of life. He still had the symptoms of nystagmus and apparent visual attention, and his ultimate diagnosis was albinism. The measurements done in these tests were crucial in demonstrating that he could see something.

Chris's results on the ERG Chris's results on the ERG