The therapy was first shown to partly restore vision in a single blind person in 2021. Photograph: fig/Getty ImagesThe therapy was first shown to partly restore vision in a single blind person in 2021. Photograph: fig/Getty ImagesGene therapy can partly restore sight in blind people, researchers revealOptogenetic therapy, based on Nobel prize-winning science, involves turning nerve cells on and off using light
A type of gene therapy based on Nobel prize-winning science is safe and can partly restore sight in blind people, researchers have revealed.
The approach, known as optogenetic therapy, harnesses the technique for turning nerve cells on and off using light that scooped the 2026 Nobel prize in physiology or medicine.
It was first shown to partly restore vision in a single blind person in 2021. Now researchers have reported the results from a larger trial involving the original patient and a further nine people.
“What we can say for sure is that the concept of optogenetics is valid for vision restoration,” said Prof Botond Roska, director of the Institute of Molecular and Clinical Ophthalmology Basel and a lead author of the study.
Roska added the aim is now to work towards restoring high-resolution vision, with the hope of achieving the goal in five to 10 years.
All 10 of the trial participants had advanced retinitis pigmentosa – a group of genetic disorders thought to affect more than 1.5 million people worldwide.
In these disorders, light-sensitive cells in the retina gradually lose their function. However, ganglion cells in the retina, which send visual information to the brain, deteriorate less quickly.
“These cells are not the primary cells targeted by the disease, so that’s why they are good candidates for the therapy,” said Dr José-Alain Sahel, another lead author of the study from the University of Pittsburgh Medical Center in the US.
The gene therapy involves giving a single injection into the eye. This injection contains a harmless, synthethic virus that delivers the genetic instructions for producing a light-sensitive protein into a ring of surviving ganglion cells. As a result, these cells are made light-sensitive.
Each patient then receives a pair of light-stimulating goggles. These capture images of the world around the patient and convert them into pulses of light of a single wavelength These pulses activate the ganglion cells that have been made light-sensitive, allowing the wearer to perceive a monochrome image.
Crucially, the technique does not depend on the exact genetic cause of the patient’s sight 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 participants’ outcomes were then followed for up to five years.
Only one severe eye-related side-effect occurred, but this was resolved within minutes, while there were no side effects related to the therapy in the rest of the body.
However, six of the 10 participants had clinically meaningful improvements in light sensitivity after the treatment.
What’s more, some of the participants showed improvements in a range of tasks when wearing the light-stimulating goggles after the gene therapy – such as detecting, locating and touching a notebook, locating a door and walking on a line.
The team added that participants who spent more time training with the goggles tended to do better on the tasks.
However, the study has limitations.
“[Patients] can detect objects, but they cannot yet detect faces,” said Roska. That, the team say, is down to the treated ganglion cells being in a ring-like arrangement around the fovea – the tiny 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, noting it provides reassurance on the safety of the approach and its application to people who still have some residual vision.
“We’ve gone from one patient to 10 patients, we’ve seen improvement in their light sensitivity … and we’ve seen that we can give a stable restoration of some visual function, some light sensitivity, that lasts for four or five years in these patients,” he said. “They’re baby steps, but they’re critical.”
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