Amblyopia is characterized by losses in a variety of aspects of
spatial vision, such as acuity and contrast sensitivity. Our goal was
to learn whether those basic spatial deficits lead to impaired global
perceptual processing in strabismic and anisometropic amblyopia. This
question is unresolved by the current human psychophysical literature.
We studied contour integration and contrast sensitivity in amblyopic
monkeys. We found deficient contour integration in anisometropic as
well as strabismic amblyopic monkeys. Some animals showed poor contour
integration in the fellow eye as well as in the amblyopic eye.
Orientation jitter of the elements in the contour systematically
decreased contour-detection ability for control and fellow eyes, but
had less effect on amblyopic eyes. The deficits were not clearly
related to basic losses in contrast sensitivity and acuity for either
type of amblyopia. We conclude that abnormal contour integration in
amblyopes reflects disruption of mechanisms that are different from
those that determine acuity and contrast sensitivity, and are likely to
be central to V1.