Researchers have demonstrated that a gene therapy based on optogenetics—a technique recognized with the 2026 Nobel Prize in Physiology or Medicine—can safely restore partial vision in people who are blind. The therapy was initially shown to improve sight in a single patient in 2021, and now a larger trial involving 10 participants has provided further evidence supporting its potential.
The trial focused on individuals with advanced retinitis pigmentosa, a group of inherited disorders affecting more than 1.5 million people globally. In these conditions, the retina’s light-sensitive cells gradually lose function, leading to blindness. However, retinal ganglion cells, which transmit visual information to the brain, deteriorate more slowly and were targeted by the therapy.
The procedure involves a single injection into the eye of a benign synthetic virus carrying genetic instructions to produce a light-sensitive protein within surviving ganglion cells. Patients then use specialized goggles that convert visual scenes into pulses of light at a specific wavelength. These pulses activate the modified cells, enabling perception of monochromatic images.
Importantly, the therapy does not depend on the underlying genetic cause of retinitis pigmentosa, broadening its applicability. The study, published in the New England Journal of Medicine, tracked participants’ outcomes over up to five years, treating only the eye with worse vision in each patient. Safety findings were generally positive, with only one serious eye-related side effect reported—one that resolved within minutes—and no systemic adverse effects.
Results showed that six of the 10 participants experienced clinically meaningful improvements in light sensitivity. Some also demonstrated better performance on practical tasks while using the goggles, such as identifying and touching a notebook, locating doors, and walking along a line. Researchers noted that greater training time with the goggles correlated with better outcomes.
Despite these advances, researchers acknowledged limitations. Participants could detect objects but were not yet able to recognize faces. This limitation is attributed to the treated ganglion cells being arranged in a ring around the fovea—the small retinal area responsible for sharp central vision—where cells remain less accessible to current therapy methods.
Prof. Botond Roska, director of the Institute of Molecular and Clinical Ophthalmology Basel and a lead author of the study, emphasized the proof-of-concept success, stating the team now aims to restore high-resolution vision within five to 10 years. Dr. José-Alain Sahel of the University of Pittsburgh Medical Center, also a lead author, highlighted the suitability of ganglion cells as targets due to their slower degeneration in retinitis pigmentosa.
Independent experts welcomed the findings. Mark Hankins, professor of Visual Neuroscience at the University of Oxford, noted that while these remain early steps, the study confirms the therapy’s safety and its potential for stable, long-term restoration of some visual function in patients with residual vision.