Berna Gomez is no ordinary 58-year-old biology teacher. At age 42, Gomez developed toxic optical neuropathy, a severe disease that destroyed the optic nerves connecting her eyes to her brain in a matter of days. Her story has been documented and has been part of a number of studies and clinical trials, notably the Journal of Clinical Investigation. Recently, a “visual prosthesis” implanted directly into the brain has allowed her to perceive two-dimensional shapes and letters for the first time in 16 years.
In 2018, at age 57, Gomez became the first patient to have a tiny 4×4-mm electrode with a hundred micro-needles implanted in the visual area of her brain. The Moran | Cortivis prosthesis bypasses the eye and optic nerve and directs signals directly to the center of visual perception in the brain. This is where the focus has been to restore her vision.
Rigorous testing and practice
After the implant was implanted, Berna spent six months in the lab: she underwent daily tests and practiced interacting with her new prosthesis. For the first 2 months, Gomez learned to distinguish spots of light through direct stimulation of the prosthesis. When more than two electrodes were stimulated at the same time, perception was easier. Some objects looked like closely spaced dots, while others looked more like horizontal lines. Vertical lines were more difficult to elicit, but by the end the patient was easily able to do this as well.
For the last month of the experiment, researchers wanted to find out if Gomez could “see” letters. She was able to identify the letters I, L, C, V, and O when simultaneously stimulated with a combination of up to 16 electrodes. She was even able to distinguish between uppercase O and lowercase O. However, stimulation patterns for the rest of the alphabet have not yet been developed.
The magic in the glasses
In the last part of the study, Gomez was given special glasses with a built-in video camera that scanned objects in front of her and then stimulated electrodes in her brain through her prosthesis, thereby creating simple visual images. As a result, Gomez learned to distinguish the contrasting boundaries of black and white stripes on cardboard.
While the results are positive to the scientific community, further testing on multiple patients is needed before the prototype is available for clinical use. It has also been established that there is no evidence indicating that the device damages the nervous system, causes epileptic seizures or other negative side effects.
Image credit: John A. Moran Eye Center at the University of Utah