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 round wafer of base out prism 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 (see the animation below).
Animation Showing How the Gottlieb System Functions
This animation demonstrates how the image missing to the right side is shifted back into the field of view of the patient. A patient approaching this intersection with a right hemianopias is able to better detect the stop sign to the right when the Gottlieb Visual Field Awarenes System is inserted.
The Visual Field Awareness System has been helpful for patients with hemianoptic field loss. The system is mounted in one lens on the side of the loss. It shifts the image about twenty degrees nasally allowing it to be detected within the remaining functional field as the patients makes mild scanning movements. Following fitting with systems, patients will require training by their therapist to learn how to use the system in the real world. Scanning training is also employed to improve the patient's functional use of their remaining visual field.