In a major breakthrough for regenerative medicine, scientists have partially restored vision in a blind man using an emerging technique called optogenetics. The approach involved injecting the patient’s eye with genes that code for light-sensitive proteins found in green algae, and represents the first successful clinical application of the technology, which enabled the patient to locate and identify objects for the first time in decades.
Some cells in the body contain proteins that make them especially sensitive to light, and by targeting these cells scientists can use light to control their behavior. Optogenetics involves inserting genes into otherwise regular cells to equip them with this kind of light sensitivity, and by stimulating these modified cells, scientists hope to develop treatments for a range of health conditions, ranging from paralysis to pain relief.
One of the more promising possibilities for this technology is in tackling progressive forms of vision loss, such as retinitis pigmentosa, which progressively destroys light-sensitive photoreceptor cells in the retina, eventually leading to blindness. Using optogenetics to implant light-sensitive proteins in the retina has long been seen as a way to address this deterioration, and we’ve seen promising early results in experiments on mice and embryonic chicks.
But these kinds of results have never been seen before in humans. Looking to change that, an international team of researchers conducted a pioneering study involving a Parisian man who was diagnosed with retinitis pigmentosa 40 years ago. The scientists injected the patient’s weakest eye with genes that encode for a light-sensitive protein called channelrhodopsin protein ChrimsonR, which is found in glowing algae and, when subjected to light, responds by changing its shape and facilitating the flow of ions in and out of cells.