Zoom Colloquium: Deficits beyond visual acuity in amblyopia

There is growing evidence that the clinical emphasis on visual acuity in both the diagnosis and the treatment of amblyopia is not sufficient. My research has focused on deficits in motion perception that are present in fellow eyes that have normal visual acuity and also in amblyopic eyes that show improved visual acuity following treatment. Deficits in motion perception occur in several developmental disorders, and they are commonly attributed to vulnerability in the dorsal visual stream. Amblyopia, however, is not a clear example of dorsal stream vulnerability because the motion deficits are most evident at slow speeds that activate regions of both ventral and dorsal visual cortex, and the well-documented spatial vision deficits involve the ventral stream. In addition to uncertain neural correlates, the real-world functional impact of deficits on computer-generated psychophysical measures of 2-dimensional motion sensitivity is not known. To address these issues, my research on amblyopia has expanded to include assessments of reading and visuomotor skills, which have more obvious functional impact and have been attributed to the functioning of the dorsal visual stream. In this talk, I will present recent data showing binocular deficits on specific components of reading ability and visually-guided reaching in children with amblyopia. Interestingly, performance on these tasks shows significant associations with stereopsis and/or motion perception.

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