A former science teacher who's been blind for 16 years became able to see letters, discern objects' edges — and even play a Maggie Simpson video game — thanks to a visual prosthesis that includes a camera and a brain implant, according to American and Spanish researchers who collaborated on the project.
The test subject had the implant for six months and experienced no disruptions to her brain activity or other health complications, according to an abstract of the study that was published this week in The Journal of Clinical Investigation.
The study furthers what it calls a "long-held dream of scientists," to impart a rudimentary form of sight to blind people by sending information directly to the brain's visual cortex.
"These results are very exciting because they demonstrate both safety and efficacy," said one of the lead researchers, Eduardo Fernández of Miguel Hernández University, in a statement. "We have taken a significant step forward, showing the potential of these types of devices to restore functional vision for people who have lost their vision."
A camera sends visual data directly to the brain
In the experiment, a neurosurgeon implanted a microelectrode array into the visual cortex of Berna Gómez, a former teacher who has been blind for more than 16 years. The implant was then paired with a video camera mounted in the center of a pair of glasses.
After a training period, Gómez was able to decipher visual information that was fed from the camera directly to her brain.
The training included a video game that helped Gómez learn how to interpret the signals coming from the electrodes. In the game, a screen suddenly shows an image of Maggie Simpson holding a gun, in either her left or right hand. The player must correctly select which hand holds the weapon; using input from the array, Gómez learned how to succeed in that task.
At the time of the study, Gómez was 57 years old. Because of her participation, including her ability to give clinically precise feedback to the scientists, Gómez was named as a co-author of the study.
Some of the prosthesis' effects were limited; it did not let Gómez identify all letters of the alphabet, for instance. But she "reliably discriminated some letters such as 'I,' 'L,' 'C,' 'V' and 'O,' " according to the study.
Further studies could use more electrodes to boost visual data
The microelectrode array was implanted through a "minicraniotomy," in a process that the researchers say "is straightforward and follows the standard neurosurgical procedures." It involves making a hole in the skull measuring 1.5-cm (a bit larger than half an inch).
The array is just 4 mm (about an eighth of an inch) square, but it holds 96 electrodes. The researchers say previous studies have found around 700 electrodes could give a blind person enough visual information to boost their mobility to a useful extent. And because the implant required only small electrical currents to stimulate the visual cortex, they're hoping to add more microarrays in the future experiments.
"One goal of this research is to give a blind person more mobility," said Richard Normann, a researcher at the John A. Moran Eye Center at the University of Utah. "It could allow them to identify a person, doorways, or cars easily. It could increase independence and safety. That's what we're working toward."
A clinical trial related to the study is scheduled to continue through May of 2024. The research is being funded through several entities, including Spain's Ministry of Science and Innovation and Miguel Hernández University, as well as the Moran Eye Center.
The method of bypassing the eyes altogether could someday restore vision to roughly 148 million people worldwide — that's how many people have had the link between their eyes and their brain severed, the researchers say, due to conditions such as glaucoma or optic nerve atrophy.
The approach used by the researchers from Utah and Spain is similar to one that was hailed last year, when scientists said they were able to get volunteers to see letters by sending electricity through electrodes on the brain's surface.
Visual impairment is one of the most common disabilities in the world and scientists are employing several strategies to help people who are affected by it. In another recent success, scientists used the CRISPR gene-editing tool to modify DNA in people to help them combat a rare genetic eye disease.
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