1. Prevention of blindness and restoration of vision in the blind. 2. Conduct interdisciplinary research on the molecular engineering, gene therapy, neurobiology, biotechnology, electrophysiology and animal behavior of prosthetic vision in the blind and other areas on the leading edge of eye research. In order to conduct the research necessary to accomplish our mission, our scientists need additional external funding support from both private and public sources.
How the Eye Works
In the human eye, light passes through the front parts of the eye – the cornea, the pupil and the lens. The retina, acting somewhat like a film, receives the light and an image is transmitted through the nearby optic nerve to the brain. The brain converts these signals into visual images that we see.
Loss of Vision
Blindness can result from a variety of diseases that affect the eye, or from injury to the eye. With most causes of blindness, some parts of the visual system remain intact. This provides an opportunity to restore vision using remaining parts of the visual system through optogenetic gene therapies. Our novel strategy for restoring vision to the blind Vision normally begins when rods and cones, also called photoreceptor cells, respond to light and send signals through other retinal neurons, called interneurons, and the optic nerve to the visual cortex of the brain and visual images are formed. Unfortunately, many inherited diseases, such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD), also strike the same photoreceptor cells in the retina. At present, no effective treatment is available for restoring vision once rods and cones, the normally light-sensitive cells in the retina, have been lost. We took a novel strategy, optogenetics, to tackle the problem by genetically converting retinal interneurons, cells that are normally not photosensitive, into photosensitive cells – thus imparting light sensitivity to retinas that lack photoreceptors. We have successfully demonstrated the feasibility of this strategy in a blind mouse model. Using a harmless virus, we introduced a gene that encodes a light-sensitive protein from green algae, called channelrhodopsin-2 (ChR2), into retinal interneurons in a strain of mice with photoreceptor deficiency that resembles the blinding disease RP in humans. We showed that the introduced ChR2 protein caused retinal interneurons to become light sensitive. Furthermore, we showed that the ChR2 protein persisted for long periods in these neurons, and the neurons generated signals that were transmitted to the visual cortex of the animals’ brains. Other centers using this same strategy have subsequently reported the restoration of certain visual behaviors in blind animal models. An important advantage of this strategy is that it does not involve the introduction of tissues or devices into the retina. In addition, it could potentially achieve high spatial resolution for the restored ‘vision’. Thus, the optogenetic strategy is a promising therapeutic treatment for restoring vision in blind individuals with photoreceptor degenerations. The first patent of our technology has been granted and several additional patent applications are pending. Also, Wayne State University has licensed the technology to a Michigan-based company, RetroSense Therapeutics, which is working to move the optogenetic therapy to human clinical trials. For related news, click here.
Our ongoing studies:
To move the optogenetic therapies to clinical applications and achieve better outcomes for restored vision in patients, current research in the Ligon Research Center focuses on the following three areas: 1) Develop and optimize the properties of optogenetic light sensors for restoring vision; 2) Develop virus-mediated targeting of optogenetic light sensors to specific inner retinal cell types and/or subcellular compartments; 3) Improve virus-mediated delivery efficiency in retinal neurons using non-human primate models. We have already made significant progress on these studies.
Meeting Our Mission
The Ligon Research Center is part of the Kresge Eye Institute, which is a nonprofit organization. This means philanthropy plays a critical role in our ability to continue with the cutting edge research and our ability to help cure blindness. Your gifts can help the center maintain its excellent reputation as one of the leaders in artificial vision research. Please consider making a financial contribution as a way to help further the care and treatments we are able to offer our patients today and into the future.