SPATIAL PROCESSING OF COMPLEX STIMULI IN THE AMBLYOPIC VISUAL-SYSTEM

  • 1 January 1982
    • journal article
    • research article
    • Vol. 23  (6) , 780-786
Abstract
Thresholds for detection and discrimination of the polarity (phase) of repetitive gratings with a ramp luminance profile were compared to sine-wave thresholds in normal and amblyopic observers. In the high-frequency range (4 cycles/1.degree.), normal observers detected ramp-wave gratings when the contrast of the fundamental spatial frequency was close to its independent thresholds and discriminated the polarity (phase) of the ramp when the 2nd harmonic reached its independent threshold. For the amblyopic eyes, detection of the ramp also occurred when the contrast of the fundamental frequency was near its independent threshold. Discrimination of the polarity (phase) of the ramp required contrast levels 2-10 times greater than needed to detect the 2nd harmonic. The reduced ability of the amblyopic eye to discriminate the polarity of the ramp represents an abnormality in phase processing and appears to be roughly proportional to the reduced optotype acuity of the amblyopic eyes.