Breakthrough research into vision restoration may result in a new type of prosthetic for people suffering from vision loss due to retinal degenerative diseases such as macular degeneration and retinitis pigmentosa.
Researchers cracked the retinal code that the retina uses to communicate with the brain. Their initial research was on mice. They determined which electrical signals the retina uses when communicating with the brain. Then, they mimicked the signals using electric-signal sending glasses in blind mice. The animals’ vision was restored to near normal.
This research is important because current vision prosthetics under development provide less specific stimulation, and are therefore limited. Until now, vision prosthetics were only sensitive enough allow basic vision that included bright light and high-contrast recognition.This technology has not yet been tried on humans. The code for monkeys has been assembled, and they should be the next species to try this new type of eye prosthetic.
This research may help patients with macular degeneration. Macular degeneration, especially age-related macular degeneration (ARMD), is the main cause of serious loss of vision in the elderly. In ARMD, the cells that detect light in the macula stop working correctly. The condition gets worse over time. A large body of peer-reviewed research indicates that nutritional support for macular degeneration may be helpful in halting or reversing the effects. As a last resort, prosthetics such as these hold out hope for restoring vision.
Retinitis pigmentosa (pigmentosis) is a disease of the retina that appears to have a strong genetic component. It typically strikes young people, starting with decreased peripheral vision and night vision. The disease affects one in 3,700 people, and it is incurable, although vitamin A has been studied as a way to manage retinitis pigmentosa. The research on the blind mice may provide a way to restore sight loss due to this disease.
The researchers started by monitoring healthy eyes to learn the set of equations that translate light that hits the retina into electrical signals that the brain can comprehend. They used special glasses to create a similar code and transmit it to the eye, which had been engineered to have light-sensitive proteins. The cells receive the code through these proteins and fire electrical impulses that the brain interprets as images.
Given that more than twenty million people around the world are blind or anticipated to become blind from retinal degenerative diseases, this research could have a significant impact on public health.
Study: “Retinal prosthetic strategy with the capacity to restore normal vision” by Sheila Nirenberg and Chethan Pandarinath. Study published in the Proceedings of the National Academy of Sciences of the United States of America, July 9, 2012.
