Abstract

In an effort to understand the neuronal basis of the abnormal visual processing that characterizes amblyopia, we have studied the development of visual performance in monkeys reared with either strabismus or unilateral image blur. We have measured vernier acuity, spatial resolution, and spatial contrast sensitivity in these animals. Compared to normal, the spatial contrast sensitivity function is displaced both downward in sensitivity and leftward in frequency in the treated eyes of these animals. They also have deficits in vernier acuity—often larger than the displacements of the contrast sensitivity functions—and we wished to know whether these were predictable from the contrast sensitivity changes. We have explored the relationship between the two measures using a contemporary spatial vision model (Watson, 1983), but this analysis requires more detailed knowledge of the empirical relation between contrast sensitivity and vernier acuity. To approach this we have measured the effect of reducing the level of illumination on human contrast sensitivity and vernier acuity. These measurements show that reducing luminance in human observers produces linked changes in both contrast sensitivity and vernier acuity resembling those seen in our abnormally reared monkeys. This suggests that the changes observed in multiple measures of visual performance may be straightforwardly related.

© 1989 Optical Society of America