A new optogenetic gene‑therapy approach, built on Nobel‑prize‑winning science, has been shown to be safe and to provide limited visual improvements in people who are legally blind due to advanced retinitis pigmentosa. The findings come from a clinical trial that treated ten participants – the original patient from a 2021 case study plus nine additional volunteers.
How the therapy works
The treatment involves a single injection of a harmless synthetic virus into the eye with the poorest vision. The virus carries the genetic blueprint for a light‑sensitive protein, which is delivered to a ring of surviving retinal ganglion cells. These cells, unlike the light‑detecting photoreceptors that degenerate in retinitis pigmentosa, remain relatively intact and can therefore be repurposed to respond to light.
After the injection, each participant wears a pair of specialised goggles. The goggles capture visual scenes and translate them into pulses of monochromatic light that activate the newly sensitised ganglion cells, allowing the wearer to perceive a black‑and‑white image of their surroundings.
Trial outcomes and safety profile
Patients were monitored for up to five years after treatment. Six of the ten participants experienced clinically meaningful increases in light sensitivity. Moreover, several individuals demonstrated functional gains on tasks such as locating and touching a notebook, identifying a doorway, and walking along a straight line while using the goggles.
Performance tended to improve with greater time spent training the goggles, suggesting that visual learning contributes to the observed benefits. Only one severe eye‑related adverse event was recorded, and it resolved within minutes. No systemic side effects were reported.
Limitations and future directions
While the therapy enabled detection of objects, participants could not yet recognise faces. Researchers attribute this limitation to the current arrangement of treated ganglion cells, which form a peripheral ring around the fovea—the retinal region responsible for sharp central vision.
Prof. Botond Roska, director of the Institute of Molecular and Clinical Ophthalmology Basel and lead author, emphasized that the concept of using optogenetics for vision restoration is now validated. He noted that the next goal is to achieve high‑resolution vision, a milestone the team hopes to reach within the next five to ten years.
Dr. José‑Alain Sahel of the University of Pittsburgh Medical Center, also a lead author, highlighted that the approach does not rely on the specific genetic mutation causing the blindness, making it broadly applicable to patients with various forms of the disease.
Independent expert Mark Hankins, professor of visual neuroscience at the University of Oxford, praised the study for confirming safety and demonstrating stable visual function lasting four to five years, describing the results as “baby steps, but critical.”
With more than 1.5 million people worldwide affected by retinitis pigmentosa, the trial offers a promising avenue for restoring at least partial sight to those who have exhausted conventional treatments.
Helene Elliott is the Lead Science & Space Reporter at News Raise. She reports on aerospace missions, astrophysics discoveries, quantum research, and environmental technology.
