A device developed in Spain returns vision by acting on the brain, not on the eyes or optic nerves. The first patient was a 57-year-old woman, Bernard Gomez, who was blind 16 years ago due to optic neuropathy.
This pathology destroys the nerves that connect the eyes to a specific part of the brain. In mild cases, this leads to impaired vision or loss of ability to distinguish colors. However, in her case, her vision was completely lost.
The device is an implant that is implanted in the brain and dark glasses equipped with a tiny camera. The device is connected to a computer that processes video in real time, converting it into electronic signals.
Using a cable connected to the port at the back of the skull, signals are transmitted to the implant. It is placed in the visual cortex and is a small chip with hundreds of spike electrodes, each of which transmits current to several neurons.
The experiment lasted 6 months, and the patient said that if she had a choice, she would prefer to leave the device. The device has a very poor resolution – 10 by 10 pixels. But it is complemented by a face recognition system based on machine learning. This allowed the woman to distinguish the outlines of objects, light and even large letters.
To understand what signal the retina generates, the researchers conducted experiments using the retina of people who had just died (it lasts up to seven hours). Implants were repeatedly tested on animals. But, unfortunately, animals cannot tell what they see.
After the operation, the device was set up for a long time. Each electrode was calibrated: scientists sent a different amount of current until the patient was able to see something. This process took more than a month.
Researchers from the University of Miguel Hernandez in Spain for 10 years working on this device. As Dr. Eduardo Fernandez, head of the research team explains, their method is different in that it does not affect the eyes.
In parallel, the development of an artificial retina is underway, and it has already been tested on the first patients. However, most of the blind (and there are 36 million in the world) have damage to the nervous system. Therefore, artificial eyes will not help them.
Dr. Fernandez says the idea of transmitting electrical signals is not new. A lot of electrical devices are used in medicine: for example, a pacemaker or a cochlear apparatus that sends signals to the implant in the inner ear.
According to scientists, the main drawback of the method is that sooner or later the implant and brain will undergo destruction. The immune system begins to reject the device and surrounds the electrodes with scar tissue, which ultimately weakens the signal.
Animal experiments show that an implant can work for 2-3 years. Scientists hope to extend this period to 10 years. In the coming years, they will conduct 5 more such operations, and perhaps new patients will wear the device for at least a couple of years.
This way to restore vision has a long history. In 1929, a German neurologist named Otfried Ferster discovered that if an electrode was inserted into the visual zone of the brain during surgery, the patient would see a white dot.
In 2000, the first implant was created. The patient writhed in pain because too much current was used to stimulate. But the device even went on sale, although it was too cumbersome and imperfect.
Another project was written last year. In the USA, implants were implanted to six people. As an experiment, they were shown a white square on a black screen, and most patients could see it