Partial Vision Restored in Some Blind Patients With New Experimental TreatmentNEWS | 14 October 2026Night vision often fades first, followed by a narrowing of peripheral vision. In retinitis pigmentosa, this progressive loss can eventually lead to blindness.
An experimental treatment has now helped some patients recover limited visual abilities.
The approach combines a gene injection with special goggles. In a small trial involving 10 people with profound vision loss in both eyes, some participants became better able to detect objects, locate them, and reach toward them while using the device.
The study in The New England Journal of Medicine was coauthored by ophthalmologist José-Alain Sahel at the University of Pittsburgh and vision researcher Botond Roska at the Institute of Molecular and Clinical Ophthalmology Basel in Switzerland.
Retinitis pigmentosa is a group of inherited disorders in which genetic changes damage the retina's photoreceptors, the cells that normally detect light.
Symptoms can begin in childhood or later, and progression varies. People without known affected relatives can also develop the disease.
Variants in more than 100 genes can cause it, complicating efforts to develop treatments for each genetic cause. This approach, called optogenetic therapy, gives nerve cells that survive the disease a new way to respond to light.
Each participant received one injection into their worse-seeing eye. A modified virus delivered instructions for producing a light-sensitive protein called ChrimsonR into retinal ganglion cells, the nerve cells that transmit visual signals toward the brain.
"The gene therapy delivers a light sensor to the blind retina, making it light-sensitive again. The goggles provide light stimulation at the wavelength to which this sensor responds," Sahel and Roska told ScienceAlert.
A camera in the goggles captures changes in brightness. A processor turns those changes into patterns of amber light, which a projector directs onto the retina to activate the protein.
An illustration showing gene delivery into the eye, retinal stimulation with amber light through special goggles, and visual testing with EEG recordings. (Courtesy of Botond Roska and José-Alain Sahel)
"In addition, the goggles adapt to outside light conditions and modify the signal to ensure optimal stimulation of the retina," Sahel and Roska said.
Participants practiced using the goggles. During visual tests, their untreated eye was covered.
The trial primarily assessed safety, but researchers also examined light sensitivity and object detection.
They measured the dimmest light participants could detect through the goggles before and after treatment. Seven showed increased sensitivity, ranging from about twofold to 62-fold. Six reached roughly a fourfold increase or more, which the team considered clinically meaningful.
That threshold came from earlier research and was not specified beforehand in the trial protocol.
Eight participants completed object tests with and without the goggles. They tried to detect, locate, and touch a notebook or small box of staples, and distinguish the orientation of a bar.
Four consistently performed better at detecting the notebook with the goggles over repeated sessions spanning roughly a year to a year and a half. Others showed no consistent improvement across the tests.
The criteria for classifying participants as responders were not specified beforehand.
"Differences between patients in the increase in sensitivity may reflect how well the gene therapy vector reaches the retinal cells, or how many retinal cells remain, or other variables such as training to wear the goggles," Sahel and Roska explained.
Better performance was associated with more training sessions, but the range of possible values included no association at all.
A study participant uses light-stimulating goggles during a test involving a notebook on a table. (Chloé Pagot/Streetlab, Paris)
Brain recordings from five selected participants supported the possibility that visual signals reached the brain. Four had already responded in behavioral tests. For some estimates, the confidence interval included zero.
"Safety was very good and is not a limitation," Sahel and Roska said. The authors cautioned that the safety findings came from 10 participants.
Researchers recorded 34 eye-related adverse events among nine participants, mostly mild or moderate. Seven developed inflammation inside the eye, which resolved with treatment without lasting consequences. One severe event involved a temporary blockage of the central retinal artery immediately after injection; it resolved within minutes after medication.
There were also 70 systemic adverse events, including six severe events. The principal investigator, with oversight from a data and safety monitoring board, judged none of the systemic events to be related to the gene therapy or injection. Three mild systemic events were linked to the goggles.
The light-stimulating goggles and portable processor used in the study. Insets show the internal projector and a camera image of a hand converted into a light pattern. (Chloé Pagot/Streetlab, Paris)
Four participants completed five years of follow-up. Several others were monitored for two to four and a half years, while two withdrew earlier.
The report expands on a 2021 study of one participant, whose results are included in the current group.
GenSight Biologics funded the trial, helped design it, and managed the data. The trial was not randomized and had no control arm. Further research is needed to assess its benefits and risks.
"What is still missing is the ability to recognize faces and to read; greater sensitivity of the optogenetic sensor would also be valuable," Sahel and Roska said.
"We are working to address these limitations."
The research has been published in The New England Journal of Medicine.Author: Esra Öz. Source
