A residual deficit for global motion processing after acuity recovery in deprivation amblyopia

In a case of bilateral deprivation amblyopia due to congenital cataracts, the global motion sensitivity for stimuli that were well within the passband of the amblyopic visual system were assessed.

A stochastic global motion stimulus was used, comprising spatially narrow elements with varied spatial frequency, density, contrast, and area distribution. To determine threshold, a two-alternate, forced-choice direction discrimination task was used.

There was a selective deficit for global motion processing that was not due to the visibility of the stimuli and was nonselective for spatial scale. The eye with the more complete recovery (acuity 20/20) from pattern deprivation in childhood exhibited the more severe global motion deficit. discussion. The results suggest a primary extrastriate deficit in the dorsal pathway, possibly involving the middle temporal (MT) and the medial superior temporal (MST) cortical areas, that is unrelated to the acuity deficit thought to be in area V1. A similar deficit has recently been shown in strabismic amblyopia.