Hemianopsia is a blindness or reduction in vision in one half of the visual field. Hemianopsia can be caused by conditions such as stroke, tumors and trauma. The cause must always be carefully investigated and diagnosed. Hemianopsia 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 hemianopsia may vary from only light or motion detection in the impaired field to just subtle decreases in sensitivity that can only be 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 often there is a physical paralysis, or paresis (weakness) on the same side of the visual field loss. If the stroke affects only the occipital lobe portion of the brain (the part of the brain that processes vision) there will result 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 InWave Hemianoptic lens and various press-on field enhancers.
Hemianoptic Mirror Systems
Mirrors have long been used to aid the patients with a hemianoptic field loss. The mirror picks up the image and reflects it into the existing visual field. The mirror provides awareness of objects and movement at the far periphery. The primary problem has been the poor cosmetic appearance.
Rear Surface Mirroring combined with a Gottlieb Visual Field Enhancement System
The posterior surface can be mirrored at the outer edge to provide additional peripheral field awareness. It will not work in some nearsighted corrections, since the angle of the peripheral lens must be very flat. From work done by my colleague, Dr. Windsor who began studying the combination of the Gottlieb system and the rear mirror in the early 1990’s, Rekindle now offers a version of this lens.
