BOSTON, Aug. 31 /PRNewswire/ -- A high-tech device that expands the visual field of patients with tunnel vision has passed a collision test in a walking simulator, according to scientists at Schepens Eye Research Institute, in a study published in the September issue of Investigative Ophthalmology and Visual Science. The study found that patients wearing this innovative device, consisting of a tiny camera, pocket-sized computer and a transparent computer display on a pair of glasses, were able to correctly judge potential collisions when "walking" in a virtual shopping mall. (Incorrect judgment could result in over reaction and actually contribute to an accident.)
"This is additional evidence that these glasses can help people with this debilitating condition," says Dr. Eli Peli, who invented them several years ago and has been testing and refining them ever since.
In previous research, Peli and his team found that the glasses significantly improved a person's ability to detect objects not in his/her visual field. The current study is the first to test the glasses while a person is in a potential collision situation.
Approximately one in 50 Americans over age 40 suffers from an eye disease, such as glaucoma or retinitis pigmentosa, that can lead to tunnel vision. Tunnel vision occurs when peripheral or side vision is destroyed, leaving only a small window of central vision. Tunnel vision can often cause the individual to bump into or trip over obstacles. "Navigating city streets or buildings can be quite challenging," says Dr. Peli.
To deal with tunnel vision, patients have relied on long canes to warn them of obstacles just in front of them. Glasses that act as reverse binoculars, miniaturizing and pulling in the missing parts of their visual field, have been tried in the past, but made things so small that detailed visual information is sacrificed.
With Peli's glasses, the transparent display allows patients to retain their ability to see detailed visual information, while also viewing a superimposed minified outline version of a wider visual field. The tiny computer-video system provides updated outline information 30 times per second. When a patient becomes aware of a possible obstacle or important object in the superimposed outline image, he/she can avoid bumping into or tripping over it.
Because the minified outline can strongly distort perception of distance and obstacle location, and only provides coarse information about the scene, Peli and his team wanted to know if patients were able to use the device to make correct judgments about potential collisions. They tested normally sighted subjects and tunnel vision patients in a large virtual mall environment that presented a series of collision scenarios -- people and objects appearing from different distances and directions. They asked the subjects to estimate the risk of collision in these scenarios with and without wearing the tunnel vision device.
The team found that, even without any adaptation or training, all tested subjects were able to make decisions using the device as accurately as when directly looking at obstacles with natural vision. The distortion of minification did not seem to affect their judgment.
The research team, which includes Dr. Gang Luo and Dr. Russell L. Woods, says that the next step is to refine the device and evaluate its utility in patients' daily life.
"From this study, we had an idea about how we could make an intelligent collision detection system. We have started to develop such a system that can automatically provide warnings about potential collisions. It can help patients with tunnel vision, as well as completely blind people," says Dr. Luo.
Schepens Eye Research Institute is the largest independent eye research institute in the nation and an affiliate of Harvard Medical School.
|SOURCE Schepens Eye Research Institute|
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