Fitting Bitemporal Field Awareness Prisms
Richard L. Windsor, O.D., F.A.A.O.
Pituitary tumors frequently result in a bitemporal hemianopsia. There is usually a loss of the outer temporal field of vision in each eye. Thus, the patient may experience a loss of the right field in the right eye and the left field in the left eye. The field loss may improve or progress after surgery. If the visual field loss does not resolve, it may cause the patient difficulty in navigating in unfamiliar areas. Patients may may bump into things on either side. Since there is some overlap of the remaining visual fields, patients only lose about 30 to 40 degrees off the outer field on each side. Bitemporal field loss is usually less debilitating than hemianoptic visual field loss. Patients, who continue to experience functional problems, may benefit from prismatic visual field awareness systems. Mary is a 64 year old female who developed a bitemporal field loss from a pituitary tumor. Mary experienced difficulty in mobility. She frequently would run into the edges of objects. To aid Mary, bilateral press-on prisms were applied in the circular design similar to the design originated by Dr. Daniel Gottlieb for the Visual Field Awareness System. The same prescription could be fabricated with bilateral Gottlieb Visual Field Awareness Systems. Mary immediately noticed that she could see objects to each side. Scanning therapy was prescribed to further improve Mary's functional abilities.
Photo: Mary's eye wear is fit with bitemporal field awareness press-on prisms.