A blind man has had his vision partially restored thanks to optogenetic therapy and protective glasses, the first successful case of such therapy in humans.
The researchers treated a 58-year-old man who for 40 years suffered from retinitis pigmentosa, a neurodegenerative eye disease in which the loss of photoreceptors can lead to complete blindness.
Retinitis pigmentosa changes the way the retina responds to light, making vision difficult, and people with the condition slowly lose their vision over time, according to the American Academy of Ophthalmology.
The scientists used a form of gene therapy to reprogram cells in the retina of the eye, injecting them with a viral vector and making them sensitive to light. “In optogenetic therapy … we create an artificial photosensitive layer on this blind retina,” explained researcher Botond Roska, a professor at the faculty of science at the University of Basel, at a news conference.
Months after the injection, the researchers fitted the patient with glasses designed that detect changes in light intensity and project corresponding light pulses onto the retina of the eye to activate the treated cells.
Although the patient was unable to recognize faces or read after treatment, he was able to perceive, locate, count and touch objects using only his treated eye while wearing the glasses, the researchers said in a study published Monday in the journal Nature Medicine.
Before treatment, the patient could not see anything with the glasses. But months after the injection, the man was able to see the white stripes in a crosswalk, detect objects such as a plate, cup or telephone, and identify furniture in a room or a door in a hallway when wearing the glasses.
“Initially the patient couldn’t see anything with the system, obviously this must have been quite frustrating. And then spontaneously he started to get very excited, reporting that he could see the white stripes across the street, ”José-Alain Sahel, professor of ophthalmology at the University of Pittsburgh School of Medicine and the Vision Institute in Paris. instructions.
The scientists also found that visual behavior corresponded to man’s brain activity. The man was the first patient in the first cohort of the study to receive adequate training before the coronavirus pandemic interrupted the investigation.
“An important milestone”
“Retinitis pigmentosa is one of the most common causes of blindness in young people and is the result of the loss of light-sensitive photoreceptor cells in the retina at the back of the eye,” Robert MacLaren, professor of ophthalmology at the Oxford University. he told the Science Media Center in London.
“In this trial, the researchers used gene therapy to reprogram other cells in the retina to make them sensitive to light and thus restore some degree of vision. This is an important milestone and new refinements will undoubtedly make optogenetic therapy a viable option for many patients in the future, ”added MacLaren, who was not associated with the study.
James Bainbridge, professor of retinal studies at University College London, said the technology “could help people whose eyesight is severely impaired.”
“It is a high quality study. It is carried out and carefully controlled. The findings are based on laboratory tests on a single person. More work will be needed to find out if the technology can be expected to provide useful insight, ”Bainbridge, who was not involved in the research, told the Science Media Center.