Originally published 2021-10-29.
In 2021 scientists in Spain and the United States reported that a tiny implant placed directly in the brain had allowed a blind woman to perceive simple shapes, lines and some letters. Berna Gómez, a former science teacher who had been completely blind for more than 16 years, wore the device for six months. It did not give her back normal sight, but it showed that a camera, a computer and a small array of electrodes could send visual information straight to the brain, bypassing the damaged eyes and optic nerves altogether.
Here is how the experiment worked, what Gómez could and could not see, and where this kind of "artificial vision" research stands today.
Who Berna Gómez is and why her eyes could not be helped
Gómez, from Elche in south-east Spain, lost her sight in her early forties to toxic optic neuropathy, a condition that damages the optic nerves. These nerves carry signals from the eyes to the brain, so once they are destroyed, even healthy eyes cannot send any picture onward. Her vision went within days.
That kind of blindness rules out many treatments that work on the eye itself, such as retinal implants, which rely on a working nerve to pass signals along. It made her a suitable volunteer for a different approach: skipping the eye entirely and stimulating the part of the brain that processes vision. In 2018, when she was about 57, she agreed to take part. She was 60 when the results were published, and she is listed as a co-author of the study.
How the implant works
The device is a Utah Electrode Array, a square of silicon just 4 millimetres on each side carrying a grid of hair-thin, needle-like electrodes; the version used here had 96 active channels. It was invented by Richard Normann of the University of Utah's John A. Moran Eye Center, and the team called the overall system the Moran|Cortivis Prosthesis.
Surgeons in Spain placed the array in Gómez's visual cortex, at the back of the brain. The rest of the system worked in three steps:
- A miniature video camera mounted on a pair of glasses captured the scene in front of her.
- Software translated the image into a pattern of electrical pulses.
- The array delivered those pulses to nerve cells in the visual cortex, which responded by producing spots of light called phosphenes.
Phosphenes are the same kind of flashes some people notice when they rub their closed eyes. By firing different electrodes in different combinations, the researchers could make Gómez see points of light arranged into simple patterns.
Six months of training: what she learned to see
Seeing with the implant was a skill that had to be learned. Gómez travelled to the laboratory every day for six months. The early weeks focused on telling real signals from the implant apart from the random flickers of light many blind people experience on their own.
She described the phosphenes as white points of light. Changing the strength of stimulation altered how bright they were, and also their tone, from whiter to more yellowish or sepia. When the researchers first managed to produce a line, she reportedly exclaimed, "I can see something!"
Over time she learned to recognise lines, basic shapes and some letters, and she could tell horizontal patterns from vertical ones, which she found harder at first, eventually with full accuracy in the tests. The team also had her play a simple video game featuring a character from The Simpsons to practise using the system.
Was it safe?
Placing electrodes in the brain carries real risks, so safety was a central question. According to the University of Utah, Gómez had no complications from the surgery, and the researchers found that the array did not damage nearby neurons or impair the function of the cortex underneath it. The array was removed at the end of the six months, as planned.
Lead researcher Eduardo Fernández of Miguel Hernández University said the results "demonstrate both safety and efficacy." The findings were published in October 2021 in The Journal of Clinical Investigation.
What this does not mean yet
It is easy to read this story as "blindness cured", but the reality is more modest. A single array with about a hundred electrodes produces a very coarse picture: a handful of dots rather than a detailed image. Gómez could identify simple patterns in controlled tests, which is a long way from reading a book, recognising faces or walking safely through a busy street.
The study also involved one person, for six months. Questions about how long such implants keep working, how the brain reacts over years, and how well results carry over to other people with different kinds of blindness still need much larger trials.
Normann's own research suggests that seven to ten arrays working together might produce more useful images. The goal, he said, is greater mobility: helping a blind person spot a doorway, a car or another person and move around more independently.
Where artificial vision research stands
Gómez's case is part of a long effort to build visual prostheses. Retinal implants came first: the Argus II, made by Second Sight, was approved in the United States in 2013 for people with retinitis pigmentosa, although its maker later stopped producing it. Retinal devices only help when the optic nerve still works, which is why brain implants like the one Gómez tested are so important for people with nerve damage.
Cortical implants date back to the experiments of William Dobelle in the early 2000s, and several groups around the world are now testing newer versions, including wireless systems with many more electrodes. Progress is real but gradual. For now, anyone with sight loss should talk to their doctor or eye specialist about the treatments, aids and rehabilitation services available today, and about whether any clinical trials might suit them.
Sources: University of Utah Health, 21 October 2021: Scientists enable blind woman to see simple shapes using brain implant; Moran Eye Center: Artificial vision news; ScienceAlert: A brain implant has allowed a blind woman to see simple 2D shapes and letters; Wikipedia: Visual prosthesis.
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