Zoom Brown Bag: Macular Degeneration: Implications for Scotoma Overlap in the Two Eyes

Abstract - I will describe two projects in the lab on functional vision in macular degeneration. Individuals with macular degeneration typically lose vision in the central region of one or both eyes. A binocular scotoma occurs when vision loss occurs in overlapping locations in both eyes, i.e. the intersection of the scotomata in the two eyes. To examine the consequences of a binocular scotoma, we carefully mapped out its extent, and measured accuracy and eye movements in a visual search task. Individuals with binocular scotomata had unique challenges (and adaptations) to visual search, while those with non-overlapping scotomas performed similarly to controls.

In another ongoing project we tested the prediction that stereopsis is impacted by the union of the two eyes’ scotomata. In other words, a scotoma in either eye will impact stereopsis, whether or not it is in a binocularly overlapping region. To test this hypothesis, we mapped the periphery with local disparity stimuli to compare functional stereopsis to the pattern of vision loss in each eye. Our results show that regions with impaired stereopsis are indeed consistent with the union of the scotoma in the two eyes.