Functional MRI as a Tool to Quantify Cortical Changes from Vision Rehabilitation

Convergence insufficiency is a vision dysfunction in which people have difficulties performing visual tasks close to them such as reading. Symptoms include headaches, eye strain, blurred and double vision, and visual fatigue. Four subjects participated in 18 hours of vision rehabilitation consisting of home and laboratory sessions. During a longitudinal study, subjects performed a simple vergence oculomotor learning task during an fMRI experiment. Spatial extent and average correlation were quantified in the following regions of interest: the frontal lobe, parietal lobe, cerebellum, and brainstem. Preliminary data suggest improved neuronal synchronization and recruitment quantified through average correlation and spatial extent respectively when comparing the blood oxygenation level dependent signal before versus after rehabilitation. These changes were sustained during a follow-up session.