Marshall Parks lecture. Binocular sensory outcomes in accommodative ET.

PURPOSE To review what is known about the normal maturational sequence for fusion and stereopsis and the binocular sensory deficits associated with accommodative esotropia (ET) and to explore the clues that accommodative ET provides about critical periods for binocular sensory function. METHODS Studies of binocular sensory function during infancy and early childhood are presented. RESULTS Most of the maturation of binocular sensory function occurs during the first year of life, yet a later abnormal visual experience-such as the onset of accommodative ET--can profoundly and permanently disrupt fusion and stereopsis. CONCLUSIONS Some binocular sensory deficits may exist before the onset of accommodative ET, but others may result directly from abnormal binocular experience. The functional organization of the maturing visual system appears to be maximally sensitive to disruption by abnormal visual experience during the first months of life, but susceptibility continues until at least 4 years of age.