Contrast sensitivity in amblyopia due to stimulus deprivation.

Contrast sensitivity functions for sinusoidal gratings of varying spatial frequency and stimulus duration were determined for both eyes of 2 patients with amblyopia due to early occlusion and lid closure. The amblyopic eyes showed reduced contrast sensitivity over a wide range of spatial frequencies and stimulus durations, and the temporal integration time of the amblyopic eye was increased by comparison with the non-amblyopic eye at high spatial frequencies. When the gratings were flickered at 10 Hz the sensitivity for both flicker and pattern detection was reduced in the amblyopic eye over the entire spatial frequency range. Abnormal flicker perception by the amblyopic eyes was also evident in the reduced photopic luminosity functions of these patients.