Vision is dependent on two factors: having a healthy eye to receive the visual information and having healthy visual processing centers in the brain to interpret and process the information. Visual processing occurs in the occipital lobe as well as the temporal and parietal lobes. The effect of stroke on vision loss is variable and often depends on the location and extent of the brain injury.
The occipital lobe processes what we think of as “vision” in terms of the visual image, but the temporal and parietal lobes are essential for visual-spatial awareness, object identification and categorization as well as facial recognition. In general, patients who have strokes or other brain injuries that affect the vision centers on the right side of the brain will have vision loss to the left (in both eyes). Patients who have strokes that affect the vision centers in the left side of the brain will have vision loss to the right (in both eyes).
The goal of vision rehabilitation in patients with stroke is to maximize visual function whether the goals are reading, mobility, or other activities of daily living. As stroke can often affect the processing of information, the cognitive and psychological aspects of a patient are commonly assessed and integrated into rehabilitation. In the Vision Rehabilitation Service, we perform functional visual field assessments and provide patients with education regarding the visual field loss as well as visual processing deficits. In addition, we evaluate prism lenses that can expand the visual field and improve awareness into the missing area of vision.
After a stroke or brain injury, the changes that a patient experiences can be permanent or there can be improvement over time. Patients can be evaluated immediately after the injury and we will continue to follow the patient closely to monitor for improvement and to continue to develop strategies to allow the patient to return to work, independent living, or to achieve their other goals.