Thanks to an innovative technique that combines gene therapy and light stimulation, the vision of a completely blind 58-year-old man has been partially restored.
The man, whose identity has not been revealed, lives in Brittany, France, and was treated in Paris. He was diagnosed with retinitis pigmentosa - which leads to the death of light-sensing cells on the surface of the retina - 40 years ago.
According to BBC, this condition affects more than two million people worldwide, and although complete blindness is rare, the man has had no vision for the past two decades.
This is the first time optogenetics enable a partial recovery of sight, said the team behind this clinical trial which involved French, American, and Swiss researchers, according to AFP.
The 58-year-old man has a genetic disease called retinitis pigmentosa, which causes light-gathering cells in the retina to die, and leads to gradual sight loss, or total blindness in some cases. Before the treatment, the man could detect some light, but optogenetics enabled him to locate and touch objects, reported the study published in the journal Nature.
In natural vision, light receptors in the retina use a protein called opsin, which reacts with the light energy that transfers the visual information to the brain through the optic nerve. In order to recover his sensitivity to the light, the patient received an injection containing a protein called "Crimson R," which detects amber light, reported the study.
The researchers waited five months after the injection, so the patient's body can have enough time to generate this protein in sufficient quantities. Then they started different trainings in which they used goggles they designed for this study. The goggles enable the display of picture in amber color on the patient's retina.
Dr. José-Alain Sahel, who founded the Institute of Vision in 2009, said: "Blind people who suffer from various types of neurodegenerative diseases in photoreceptors, but still have a functional optic nerve, are likely more eligible for this treatment."
