Binocular combination in children with deprivation amblyopia

Abstract

Purpose: Binocular combination is possible in many patients with strabismic, anisometropic or mixed amblyopia when contrast is appropriately balanced between the eyes. We tested the hypothesis that children with deprivation amblyopia, due to a history of early childhood cataract, are also capable of binocular combination.

Methods: Thirty-six children (mean age 9±2years) with a history of early bilateral cataract (n=9), early unilateral cataract (n=8), anisometropic amblyopia (n=9) or normal vision (n=10) were recruited. Binocular combination was assessed using an established dichoptic global motion paradigm, whereby high contrast signal elements are presented to the amblyopic or non-dominant eye and noise elements are shown to the fellow or dominant eye with varied contrast. A measurable motion coherence threshold indicates binocular combination of the signal and noise elements.

Results: Binocular combination could be measured for 7 of 9 bilateral deprivation cases, 5 of 8 unilateral deprivation cases, and all participants with anisometropic amblyopia or normal vision. Children with bilateral or unilateral deprivation amblyopia required significantly larger interocular contrast differences for binocular combination than children with anisometropic amblyopia or normal vision (p < 0.05).

Conclusions: It was possible for the majority of children with deprivation amblyopia to combine information from both eyes when contrast was appropriately balanced, although large interocular contrast differences were required. This suggests that treatments targeting binocular function may be effective in some cases of deprivation amblyopia.