Another incredible advance in science: the totally blind man who must see for the first time

A team of scientists announced on Monday that had partially restored a blind man’s sight by building proteins that pick up light in one of his eyes. His report, published in the magazine Nature medicine, is the first published study to describe the successful use of this treatment.

“Seeing for the first time that it worked, even if only in one patient and one eye, is exciting“, He said Ehud Isacoff, neuroscientist of University of california, Berkeley, who did not participate in the study.

The procedure is far from complete. The volunteer, a 58-year-old man who lives in France, he had to wear special glasses that gave him the ghostly perception of objects in a narrow field of vision. But the report’s authors say the trial – the result of 13 years of work – is proof of concept for more effective treatments in the future.

“Obviously, this is not the end of the road, but it is an important step“Said Dr. José-Alain Sahel, an ophthalmologist who divides his time between University of Pittsburgh and the Sorbonne in Paris.

Sahel and other scientists have been trying for decades to find a cure for inherited forms of blindness. These genetic disorders deprive the eyes of essential proteins necessary for vision.

When light enters the eye, it is captured by calls cells photoreceptors. The photoreceptors then send an electrical signal to their neighbors, called cells ganglion, which can identify important characteristics such as movement. They then send their own signals to the optic nerve, which sends the information to the brain.

In previous studies, researchers were able to treat a genetic form of blindness called Leber’s congenital amaurosis, by repairing a defective gene that would otherwise cause photoreceptors to degenerate gradually.

But other forms of blindness cannot be treated so easily, as their victims completely lose their photoreceptors. “Once the cells die, the genetic defect cannot be fixed“, He said Sahel.

For these diseases, Sahel and other researchers have experimented with a more radical type of repair. They use the gene therapy to transform ganglion cells into new photoreceptor cells, although they do not normally pick up light.

The scientists take advantage of proteins derived from algae and other microbes that can make any nerve cell sensitive to light.

At the beginning of the 2000’s, neuroscientists discovered how to install some of these proteins in the brain cells of mice and other animals by injecting viruses carrying their genes. The viruses infected certain types of brain cells, which then used the new gene to build light-sensitive channels.

Researchers originally developed this technique, called optogenetics, as a means of probing the functioning of the brain. By inserting a small light into the animal’s brain, they could turn a certain type of brain cell on or off with the flick of a switch.. The method allowed them to discover the circuits underlying many types of behavior.

Sahel and other researchers wondered if they could use the optogenetics to add light-sensitive proteins to retinal cells. After all, they reasoned, retinal cells are nerves too; in other words, an extension of the brain.

In order to Ed Boyden, neuroscientist at MIT. – who helped pioneer the field of optogenetics – the quest to use these proteins to cure blindness took him by surprise. “So far, I have thought of optogenetics as a tool primarily for scientists, as it is used by thousands of people to study the brain.“, He said. “But if optogenetics are clinically proven, that would be extremely exciting.“.

the Dr. Sahel and his colleagues recognized that protein optogenetics created by the Dr Boyden and others were not sensitive enough to produce an image from ordinary light entering the eye. But scientists could not emit amplified light towards the eye, because the glare would destroy the delicate tissue of the retina.

Scientists therefore chose a protein optogenetics which is only sensitive to amber light, which is more pleasing to the eye than other colors, and they used viruses to transport these amber proteins to the ganglion cells in the retina.

Then, researchers invented a special device to transform visual information from the outside world into amber light that could be recognized by ganglion cells. They created glasses that analyze your field of vision thousands of times per second and register the pixels by which the light changes. The glasses then send an amber pulse of light from that pixel to the eye.

The researchers believed that this strategy could create images in the brain.. Our eyes naturally roll in small movements several times per second. With each jump, many pixels would change the light levels.

Yet the question remained open whether the blind could learn to use this information to recognize objects. “The brain must learn a new language“, He said Botond Garbage, ophthalmologist University of Basel and co-author of the new study.

After testing his gene therapy and protective eyewear on coveralls, the Dr Roska, Dr Sahel and their colleagues were ready to test it on people. His plan was to inject viruses with genes into one eye of each blind volunteer, then wait several months for the ganglion cells to develop optogenetic proteins. They then trained the volunteers to use the glasses.

Unfortunately, they only managed to train one volunteer before the coronavirus pandemic brought the project to a halt.. After years of preparing for the studio, he was now stuck in limbo.

But then the only volunteer they had managed to train got in touch. For seven months he had worn the glasses at home and on walks. One day he realized he could see the stripes of a crosswalk.

When the pandemic subsided France Over the summer, scientists managed to bring it to their lab for further training and testing. They found he could reach out and touch a notebook on a table, but was less fortunate with a small box of staples.. When the scientists placed two or three glasses in front of the volunteer, he was able to count them correctly 12 out of 19 times.

During some tests, the volunteer wore a cap with electrodes capable of detecting brain activity through his scalp. When the glasses sent signals to his retina, they activated parts of the brain involved in vision.

“EIt is a great achievement from a scientific point of view, and especially for the blind“, He said Lucy Pellissier, neuroscientist of University of Tours in France who did not participate in the study.

Sahel and his colleagues founded a company called GenSight to move his technique to clinical trials in the hopes that regulators would approve it. They are not alone. Isacoff and his colleagues founded a similar company called See the biography which was acquired last October by Novartis.

Many more positive clinical trial results will be needed before optogenetics becomes standard treatment for some forms of blindness. For now, the Dr. Sahel and his colleagues bring in the other volunteers to train them, as well as testing higher doses of the virus and improving your glasses with thinner glasses that would be more comfortable and, at the same time, they would provide more information to the retina.

the Dr Isacoff and his colleagues conducted their own experiments that raised the possibility that other optogenetic proteins could make retinal cells sensitive enough to detect light without the aid of glasses. “I think it will work pretty well“, He said.

As long as the Dr. Sahel He devoted himself to his own system, hesitating to guess how much it could improve. “Until a patient tells you what they see, you can’t really predict anything“, He said.

(C) The New York Times.

KEEP READING: