A New Way to Detect Vision Loss ~ GAMES AND GADGETS

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Saturday, January 12, 2008

A New Way to Detect Vision Loss

Scientists at Schepens Eye Research Institute have discovered that a visual illusion called the induce twinkle after-effect (TAE) is a simple and cheap way to detect vision loss and other eye diseases in patients and also helps keep track of a patient's vision loss. According to the scientists, the induced twinkle after-effect can accurately identify the location as well as the extent of the visual loss in people suffering from retinal disease.

The twinkle after-effect is what scientists call the phenomenon when a person sees a "twinkling" in a blind spot after staring at a noisy visual target and then staring at an empty screen. The "twinkle after-effect" has been discovered by scientists in as early as 1992. Scientists have discovered that when a person looks at a TV screen with static noise while part of their visual field is covered with a patch, they experience a twinkling sensation in the patched area after the noise is turned off and the person stares at an empty screen. One patient even described the other areas that don't experience the twinkling sensation as something that looked like a moving cumulous cloud. Dr. Peter Bex, an associate scientist at Schepens Eye Research Institute says that while the discovery is interesting, scientists didn't exactly know how it could be used for patients.

However, Bex's team was able to realize the potential use of the twinkling effect. They have theorized that the blind spots that persons could see after staring at a noisy screen and then looking at a blank screen could be easily mapped.

Bex and his team tested their theory by asking eight patients suffering from macular degeneration to undertake a microperimetry test and the "twinkle after-effect" test. After staring at a noisy screen, they provided the patients with a blank touch screen so they can map out the twinkling areas with their fingers. 75 percent of the two tests matched and some visual defects were detected in areas that were not accessible to microperimetry. Bex believes that the results prove that the "twinkle after-effect" can be used as a diagnostic tool. He says that TAE cannot replace the more sophisticated methods of detecting vision loss, however, TAE is powerful, simple, and inexpensive, which patients can use in the privacy of their own homes.

Currently, the traditional method of detecting blind spots is expensive and time consuming. Retinal specific microperimetry alone costs 50 thousand dollars. Dr. Bex hopes that they can make this simple technique available online or through DVD so patients can monitor changes in their vision and have a physician study it more closely.


Schepens Eye Research Institute

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