Reorganization of visual processing is related to eccentric viewing in patients with macular degeneration

Neural evidence exists for cortical reorganization in human visual cortex in response to retinal disease. Macular degeneration (MD) causes the progressive loss of central visual acuity. To cope with this, MD patients often adopt a preferred retinal location (PRL, i.e., a functional retinal area in their periphery used to fixate instead of the damaged fovea). The use of a PRL may foster cortical reorganization.

We used fMRI to measure brain activity in calcarine sulcus while visually stimulating peripheral visual regions in MD patients and age-matched control participants.

We found that visual stimulation of the PRL in MD patients increased brain activity in cortex normally representing central vision relative to visual stimulation of a peripheral region outside the patients' PRL and relative to stimulation in the periphery of age-matched control participants.

These data directly link cortical reorganization in MD to behavioral adaptations adopted by MD patients. These results not only confirm that large-scale cortical reorganization of visual processing occurs in humans in response to retinal disease, but also relate this reorganization to functional changes in patient behavior.