Blind patients regain partial sight with novel gene-goggle therapy: Details inside

After peripheral vision of an individual narrows, changes in central vision and colour perception come next in the progression of retinitis pigmentosa (RP), further leading to blindness. Researchers have come up with an experimental treatment which has helped some patients recover limited visual abilities. The method combines a gene injection using distinctive goggles.

It was developed using a small trial involving 10 people with profound vision loss in both eyes. Following the treatment, some participants developed better vision with the ability to detect objects, locate them, and reach toward them while using the device.

The New England Journal of Medicine has published the study, which 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.

What is Retinitis pigmentosa?

It is a family of inherited disorders in which genetic mutations damage the photoreceptors of the retina, the cells responsible for detecting light. Onset can occur in childhood or later in life, and the disease progresses at different rates; it can also arise in people with no known family history.

Because changes in more than 100 different genes can trigger it, developing a treatment for each genetic cause has proven difficult. The approach being tested, known as optogenetic therapy, equips surviving nerve cells with a new mechanism for responding to light.

Each participant was given a single injection in their weaker eye, through which a modified virus carried instructions for retinal ganglion cells — the nerve cells that carry visual information to the brain- to produce a light-sensitive protein called ChrimsonR. "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.

The goggles pair a built-in camera, which detects brightness changes, with a processor that translates these into amber light patterns, projected onto the retina to activate the protein. "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 trained with the goggles and underwent vision tests, with their untreated eye covered and assessed for light sensitivity and object detection. Researchers later found that participants with low vision could see through the goggles both before and after treatment. Post-treatment, seven participants showed heightened sensitivity — ranging from roughly twofold to 62-fold, with six reaching close to a fourfold increase or more, a benchmark drawn from prior research rather than set in advance by the trial protocol.

Eight participants underwent object-based testing with and without the goggles, attempting to detect, locate, and touch a notebook or a small box of staples, and to identify a bar’s orientation. Four showed consistently better notebook detection with the goggles across repeated sessions over roughly a year to eighteen months, while others showed no steady improvement. The study did not predefine criteria for identifying participants as responders.

"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.

More training sessions correlated with better performance, though confidence intervals left room for no effect. Brain recordings from five participants suggested visual signals reached the brain. Safety was deemed “very good,” based on 10 participants: 34 eye-related and 70 systemic adverse events occurred, mostly mild, with none of the systemic events linked to the therapy. Follow-up ranged from two to five years. GenSight Biologics funded the non-randomised, uncontrolled trial; further research is needed.