Hemianopsia is a blindness or reduction in vision in one half of the visual field. Hemianopsias can be caused by conditions such as stroke, tumors and trauma. The cause of a hemianopsia must always be carefully investigate by the patient's physicians. Hemianopsias may vary from an absolute loss of all vision on one side to a relative loss where vision is reduced, but not completely missing. Relative hemianopsias may vary from light or motion detection only in the impaired field to only subtle decreases in sensitivity demonstrated on careful visual field testing. The defect is called a homonymous hemianopsia when the field loss presents on the same side in both eyes. This is typical of stroke and patient suffering right or left arm or leg weakness may also present a homonymous hemianopsia on the same side of the weakness. Pure occiptal lobe stroke, affecting the part of the brain that processes vision may result in a homonymous hemianopsia without any other impairment or paralysis.
During the first few months after a stroke or trauma, some improvement in visual fields may be possible, but recovery depends on the extent of the damage. There are no specific treatments to cure the field loss, but today we have optical devices and therapies that help most patients compensate for their visual field loss. These optical systems include the Gottlieb Visual Field Awareness System, the Peli lens and various press-on field enhancers.
The application of a prism to enhance visual field has existed for many decades. However, the development of the Gottlieb Visual Field Awareness System has greatly improved our success rates in aiding patients after hemianoptic visual field loss. Gottlieb's novel approach was to abandon the traditional equal prism in each side in a straight line and rather place a small wafer of base out prism in a round shape on the side of the visual field loss. The idea is to shift the image into the patient's still functional field as the patient makes natural scanning movements.
Understanding Hemianopsia, an article recently published by Dr Laura and Richard Windsor
Patient Stories Stroke and Head Injury
