A homonymous hemianopsia is the loss of one half of the field of view on the same side in both eyes. It occurs frequently in stroke, traumatic brain injuries, and brain tumors. It is due to the way a portion of the optic nerve fibers from each eye crossover as they pass to the occipital lobe. The occipital lobe is the posterior portion of the brain responsible for vision.
The visual images that we see to the right side travel from both eyes to the left side of the brain. The visual images we see to the left side travel from both eyes to the right side of the brain. Therefore, damage to the right side of the posterior portion of the brain can cause a loss of the left field of view in both eyes. Likewise, damage to the left side of the posterior brain can cause a loss of the right field of vision in both eyes.
Our side (peripheral) vision allows us to distinguish approaching objects without having to think about it. When a moving vehicle passes in front of us, we are not startled, because we detected it and sensed it was coming. When someone loses part of their side vision due to a hemianopsia, however, objects may suddenly appear, often startling them. Patients also report a fear of falling, tripping, or running into objects. Others knock over drinks, and are easily startled by objects or people that suddenly appear out of nowhere.
Homonymous hemianopsia patients may feel unsafe in crowded areas. They can easily become lost, feel disoriented and unable to navigate safely. Some patients, fearing both embarrassment and the potential for injury, may become socially withdrawn.
To further complicate matters, some homonymous hemianopsia patients may mistakenly believe that the loss of vision is limited to just one eye. They may report, “my left eye has been bad since the stroke.” In reality, the damage in the brain caused a visual field loss in both eyes. Hemianopsia patients also routinely fail to fully report the degree of their visual disability. It is not uncommon for such patients to deny the loss of visual field and to report no visual deficiencies. However, caregivers observe them running into objects, tripping, and being startled.
Dr. Winkler utilizes special prismatic visual field expander lenses to help patients return to a more normal life. These lenses incorporate special high-powered prisms. The prisms project an artificial-type of peripheral vision into the non-blind portion of the patient’s visual field. This promotes motion detection and object avoidance. The potential to improve visual function and mobility is thus made possible by using prisms to expand the visual field.
The patient is first given temporary test prisms in the office that adhere to their eyeglasses. If this is successful, they take the glasses/prism combo home to evaluate in their own environment. Only after they are successful at home are the final glasses lenses ordered from the laboratory.
To contact Dr. Winkler’s office about treatment for Hemianopsia, please click here.
Dr. Todd Winkler, 8154 Montgomery Rd, Cincinnati, OH 45236 (513) 791-3556