A new eye implant combined with high-tech glasses has enabled people with severe age-related macular degeneration to read again. The device, called PRIMA, was tested in a study of 32 participants over one year. It provides black-and-white vision by converting images into electrical signals for the retina.
Age-related macular degeneration (AMD) damages light-sensitive cells in the retina's center, impairing central vision and making tasks like reading or recognizing faces difficult. Existing treatments only slow progression, but a novel device offers restoration for advanced cases known as geographic atrophy.
Developed by Daniel Palanker at Stanford University and colleagues, PRIMA consists of a tiny 2-by-2-millimetre wireless chip implanted in the eye's back, powered by solar energy. A camera on special glasses captures images and projects them via infrared light onto the chip, which converts the data into electrical signals that remaining retinal neurons transmit to the brain. Infrared avoids interference with any natural vision. "This means patients can use both prosthetic and central vision simultaneously," says Palanker.
In a trial published in the New England Journal of Medicine (DOI: 10.1056/NEJMoa2501396), researchers recruited 32 people aged 60 or older with vision worse than 20/320 in at least one eye. The chip was implanted in one participant initially, followed by glasses use after four to five weeks. The glasses magnify images up to 12 times and adjust brightness and contrast.
After one year, 27 participants regained reading ability, shape and pattern perception, and an average improvement of five lines on eye charts. Some achieved vision equivalent to 20/42. One patient remarked, "I thought my eyes were dead and now they are alive again," according to José-Alain Sahel at the University of Pittsburgh.
About two-thirds experienced temporary high eye pressure, but it did not hinder gains. The vision remains black and white; future updates aim for grey scales and better resolution, potentially reaching 20/20 with zoom. Francesca Cordeiro at Imperial College London called it "an exciting and significant study" offering hope where restoration seemed like science fiction.
While stem cell and gene therapies are experimental, PRIMA is the first prosthesis to restore functional sight in AMD patients with geographic atrophy.