Science fiction is filled with examples of characters having bionic implants. Two of the most famous examples are from the television programs The Six Million Dollar Man and Star Trek: The Next Generation, which feature characters with bionic eye implants. What about the here and now? There are cochlear implants for persons who are deaf. Is there something for persons who are blind? Well, there have been important developments in this area and there are devices that are providing vision both to laboratory mice and in people.
Eye Implant & Special Glasses
One of the leading causes of blindness is age-related macular degeneration (AMD). Current treatments only help preserve what vision is left and they can’t restore lost vision. In a trial done in Europe, 38 patients, all of whom had geographic atrophy, an advanced stage of dry AMD, were able to read again as a result of both a wireless chip implanted in the back of the eye and specialized augmented reality glasses.
In this study, which was reported in the New England Journal of Medicine, participants were fitted with a device known as PRIMA. They wore augmented reality glasses with a camera that captures their field of vision and carried a separate image processor that allows patients to zoom in and magnify the images. Images captured by the camera are transmitted to the chip implanted in the eye in the form of infrared light, which is converted into an electrical current. This stimulated the remaining healthy cells in the macula and enables them to interpret the signals as vision.
While images appear in black and white, 80 percent of the 32 patients who returned for a one-year reassessment had clinically meaningful visual improvements. One patient who was fitted with the device described her life before the implant as having “two black discs in my eyes.” Now that she had the implant, she is able to do crossword puzzles and read prescriptions.
This device is not without its limitations and risk. There is the surgery needed to implant the device and that requires lifting the retina off its normal position to implant the device and that can increase atrophy. Also, there is the fact that images are not transmitted in color and patients have to be trained to learn how to see with the device. Even with the limitation, the PRIMA device has potential and over time improvement can be made to this, and other devices that will one day give patients with AMD and other diseases that lead to blindness, a chance to regain their vision.
Biologic Implant
The PRIMA device isn’t the only viable implant that can provide vision to people who are blind. Work done at Scripps Research showed that vision loss for people with a rare retinal disorder called macular telangiectasia type 2 (MacTel) can be slowed with the use of a neuroprotective surgical implant.
The study dealt with two phase 3 clinical trials evaluating a surgically implanted device ENCELTO that releases a therapeutic protein to preserve vision. These clinical trials were done in 47 sites around the world, 228 people with MacTel were enrolled and their progress was followed for 24 months.
The implant delivers a naturally occurring protein that protects the retinal neurons, known as ciliary neurotrophic factor (CNTF). It also has genetically modified retinal pigment epithelial cells. These cells help nourish and support the retina and it is housed in a tiny, collagen-based capsule, which is implanted in the back of the eye. The capsule design protects the cells from immune rejection while it releases CNTF.
This study showed that ENCELTO slowed the loss of photoreceptors, the light-sensing cells that are needed for central vision. In one of the trials, the implant led to a 54.8 percent reduction in the rate of ellipsoid zone loss, which is a change in the retina’s structure that reveals photoreceptor cell degeneration. Another trial shows a 30.6 percent reduction of the same measure.
Several measures of visual function were measured, such as a test of retinal light response and reading speed. While the results from test of retinal light response showed a slowing of visual loss, results from reading speed and retinal sensitivity tests were mixed.
Despite this variability, the trend across trials supports the implant’s long-term benefits, especially when treatment is started before widespread cell loss. Participants were able to tolerate the implant and there were minimal side effects. Another good thing about ENCELTO is that it was effective regardless of the subject’s baseline vision or disease stage. This signifies that starting treatment in the early stages of the disease process may help to preserve more functional vision.
“This is a step toward redefining how we think about vision loss,” says one of the corresponding authors, Professor Martin Friedlander of Scripps Research. “Instead of waiting for cells to die, we’re learning how to protect and preserve them.”
While both the PRIMA device and the ENCELTO implant are at the earliest stages of use, they show how research is working towards restoring vision to those who lost it due to AMD or Mac-Tel. Whether the treatment is bionic or biologic based, the PRIMA device and the ENCELTO implant don’t just maintain the status quo, they lead to improved vision and a better quality of life.
https://www.scripps.edu/news-and-events/press-room/2025/20250801-friedlander-encelto.html