Scientists in France have partially restored the eyesight of a blind man using gene therapy – now, he is able to identify blurry shapes
In late 2020, scientists at Trinity College Dublin found that gene therapy could successfully protect he visual function of mice who were treated with a chemical targeting the mitochondria and were consequently living with dysfunctional mitochondria. The scientists also found that their gene therapy improved mitochondrial performance in human cells that contained mutations in the OPA1 gene – meaning that this could also work in humans, one day.
Professor Farrar, part of the OPA1 study, said at the time: “It is important to highlight that there is still a long journey to complete from a research and development perspective before this therapeutic approach may one day be available as a treatment.”
Yesterday (24 May), a journal article was published that documented the restoration of partial vision to a human being with blindness.
What kind of blindness was treated?
Retinitis pigmentosa (RP) is a progressive, inherited, monogenic or rarely digenic blinding disease caused by mutations in more than 71 different genes. It affects more than 2 million people worldwide. With the exception of a gene replacement therapy for one form of early-onset RP caused by mutation in the gene RPE65.
Currently, there is no approved therapy for RP.
The main subject of this study was a 58-year-old man who was diagnosed with Retinitis pigmentosa, 40 years ago. When he begun the experiment, he could sense light only – if it was there or not.
The combination of special goggles and injections
The study is the first evidence that the injection of optogenetic sensor-expressing gene therapy vector (gene therapy) in combination with light-stimulating goggles, specially engineered to provoke the eye to see, can create a partial vision.
It took seven months after the beginning of ‘visual training’ for the man to be able to perceive objects. The researchers say that this training meant teaching the patient “to become aware of the direction of his gaze and to control his eye movements to be able to look straight into the light beam projected by the goggles.”
The goggles projected light straight into the eye. But before this stage of light and glasses, an injection was given.
What was injected?
A specific type of virus can provoke the brain to build light-sensitive channels. The team gave this man a protein that is sensitive to amber light, using viruses to deliver the protein directly into the retina. This process is vaguely, loosely similar to how some vaccines work – the good stuff is delivered via a virus, which then provokes the immune system to create a really useful response.
Botond Roska, an ophthalmologist at the University of Basel and a co-author of the new study, said: “The brain has to learn a new language.”
The team placed objects on a white table in front of him, and asked him to identify where they were. After visual improvement, it was still the larger objects that were more easy for him to locate.
The team will now begin building lighter, less cumbersome goggles and trying this process out on others to see how the results hold up. A freely available therapy for blindness is still distant, but it more partially visible than it ever was.