Chemical Found to Restore Light Perception in Blind Mice
A new study gives hope to those individuals who suffer from blindness caused by progressive degeneration of photoreceptors in the eyes. These rods and cones are the source of blinding diseases which include retinitis pigmentosa and age-related macular degeneration. A science article in Science Daily news reports on a study performed by Dr. Richard Kramer of the University of California and colleagues. The study resulted in the invention of “photoswitch” chemicals that bestow light sensitivity on ganglion cells that are otherwise light-insensitive. The end result was the restoration of light perception in blind mice.
A previously used photoswitch required the use of very bright ultraviolet light, which made it inappropriate for medical use. The new chemical, DENAQ, responds to normal daylight with a single injection, resulting in light-sensitivity that lasts for several days. The experiment included mice with degenerated, functional and nonfunctional rods and cones, showing that only those that had ganglion cells which had already died were impacted by the chemical. The researchers determined that the change in electrophysiology of the inner retina that occurs from degeneration enables the photosensitization from exposure to DENAQ, while those with intact photoreceptors resist it.
These results are exactly in line with requirements for an effective drug for restoring vision. This will allow treatment of the diseased tissue, without causing side effects in the healthy tissue. While additional studies will be needed to determine the safety and effectiveness of short-term and long-term treatment, the results of the study offer hope for a more effective treatment for some vision diseases.