An experimental optogenetic treatment increased light sensitivity in 7 of 10 blind participants with advanced retinitis pigmentosa. Six reached the study’s threshold for a clinically meaningful improvement.
The results were published October 7 in The New England Journal of Medicine. Participants received an injection in one eye of a treatment carrying genetic instructions for ChrimsonR, a protein that responds to red light. They then used special goggles that convert images of their surroundings into light signals designed to activate retinal cells.
Photoreceptors that normally detect light are gradually lost in retinitis pigmentosa, while retinal ganglion cells are relatively preserved. The therapy was intended to make those cells responsive to light so they could relay visual information to the brain.
The study found increased light sensitivity in 7 participants. Six met the researchers’ threshold for a clinically meaningful change. This did not amount to normal sight. The authors reported partial visual function in a small, open-label trial. Optogenetic therapy first partially restored sight in a patient in 2021.
Researchers recorded 34 eye-related adverse events in 9 participants, most of them mild or moderate. One severe event, a temporary blockage of the central retinal artery after injection, resolved within minutes after treatment. The authors said further research is needed to assess safety and efficacy.
Botond Roska, director of the Institute of Molecular and Clinical Ophthalmology Basel and a study author, said the findings support the potential of optogenetics. He said the next goal is to restore more vision, which could take 5 to 10 years. The method of controlling cell activity with light received broad recognition when the 2026 Nobel Prize in Physiology or Medicine was awarded for work on optogenetics.