First Human Test of Optogenetics Could Restore Sight to the Blind

Before our brains build a visual image of our world, a chain of cells in our eyes must convert light into electrical signals that are processed in the brain. Photoreceptor cells in the retina represent the first link in this chain, and they are reactive to photons, or the fundamental particle of visible light. Retinitis pigmentosa causes these cells to degenerate, and patients with this condition lose peripheral and night vision and eventually go blind. The plan is to bypass these broken photoreceptor cells and make ganglion cells, which relay signals from the retina to the brain, sensitive to light.

In a trial sponsored by RetroSense Therapeutics, doctors from the Retina Foundation of the Southwest will inject a harmless virus loaded with DNA from photoreceptive algae into the eyes of 15 patients suffering from retinitis pigmentosa, in an attempt to transfer the job duties of photoreceptor cells to different cells in the eye to restore sight.

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