A type of gene therapy based on Nobel Prize-winning science is safe and can partially restore sight in blind people, researchers have revealed.
The approach, known as optogenetic therapy, exploits the technique of turning nerve cells on and off using light that won the 2026 Nobel Prize in Physiology or Medicine.
It was first shown in 2021 to partially restore vision in a blind person. Researchers have now reported the results of a larger trial involving the original patient and nine other people.
“What we can say with certainty is that the concept of optogenetics is valid for vision restoration,” said Professor Botond Roska, director of the Basel Institute of Molecular and Clinical Ophthalmology and lead author of the study.
Roska added that the goal now is to work toward restoring high-resolution vision, with the hope of achieving that goal within five to 10 years.
All 10 trial participants had advanced retinitis pigmentosa – a group of genetic disorders thought to affect more than 1.5 million people worldwide.
In these disorders, the photosensitive cells in the retina gradually lose their function. On the other hand, the ganglion cells of the retina, which send visual information to the brain, deteriorate less quickly.
“These cells are not the main cells targeted by the disease, which is why they are good candidates for treatment,” said Dr José-Alain Sahel, another lead author of the study from the University of Pittsburgh Medical Center in the US.
Gene therapy involves administering a single injection into the eye. This injection contains a harmless synthetic virus that delivers the genetic instructions to produce a light-sensitive protein in a ring of surviving ganglion cells. As a result, these cells become sensitive to light.
Each patient then receives a pair of light-stimulating glasses. These capture images of the world around the patient and convert them into pulses of light of a single wavelength. These impulses activate ganglion cells made sensitive to light, allowing the wearer to perceive a monochrome image.
Importantly, the technique does not depend on the exact genetic cause of the patient’s vision loss.
Writing in the New England Journal of Medicine, the researchers report how, for each patient, they treated only the eye with the worst vision, adding that the participants’ results were then followed for five years.
Only one serious eye-related side effect occurred, but it resolved within minutes, while there were no treatment-related side effects in the rest of the body.
However, six of the ten participants showed clinically significant improvements in their light sensitivity after treatment.
Additionally, some participants showed improvements in various tasks when wearing light-stimulating glasses after gene therapy – such as detecting, locating and touching a notebook, locating a door and walking a line.
The team added that participants who spent more time practicing with the glasses tended to perform better on the tasks.
However, the study has limitations.
“(Patients) can detect objects, but they can’t detect faces yet,” Roska said. According to the team, this is because the treated ganglion cells are arranged in a ring around the fovea – the small pit in the retina responsible for sharp central vision.
Mark Hankins, professor of visual neuroscience at the University of Oxford, who was not involved in the work, welcomed the study, stressing that it provides reassurance about the safety of the approach and its application to people who still have residual vision.
“We went from one patient to 10 patients, we saw an improvement in their light sensitivity…and we saw that we can stably restore some visual functions, some light sensitivity, that lasts for four or five years in these patients,” he said. “These are small steps, but they are essential. »
Gn Health
