Groundbreaking results from an international clinical trial led by researchers at Stanford Medicine are opening a new chapter in the treatment of age-related vision loss. In 27 patients with advanced age-related macular degeneration (AMD), the innovative PRIMA eye implant restored the ability to read and recognize shapes—something that was previously impossible with this type of retinal damage.
The study, published on October 20, 2025, in the prestigious journal The New England Journal of Medicine, involved 38 patients over the age of 60 suffering from geographic atrophy, an advanced form of AMD. All had significantly impaired visual acuity – worse than 20/320 in at least one eye – and underwent implantation of a wireless PRIMA chip. They then wore special glasses equipped with a camera that transmits real-time images to the implant for one year.
The PRIMA system consists of a microscopic 2×2 mm chip implanted under the retina and smart glasses. A camera mounted in the glasses records the image and transmits it in the form of infrared light to the chip, which converts the signals into electrical impulses, thereby stimulating the remaining retinal cells to transmit information to the brain. As the authors of the study emphasize, this is the first device that restores so-called form vision, i.e., the ability to recognize shapes and patterns, not just light.
Of the 32 patients who completed the one-year testing period, 27 regained the ability to read, 26 showed clinically significant improvement in visual acuity (at least two lines on the eye chart), with an average improvement of five lines and one patient improving by as much as twelve lines.
Patients successfully read books, food labels, and subway signs. Thanks to the glasses’ digital features, such as contrast and brightness adjustment and up to 12x image magnification, many of them regained independence in their daily lives. Two-thirds of participants rated the device as very useful. Nineteen patients experienced side effects such as increased eye pressure, peripheral retinal tears, and minor subretinal hemorrhages. All symptoms resolved within two months and none were life-threatening.
The current version of the PRIMA implant allows for black-and-white vision, but the research team is already working on software that will enable the perception of shades of gray, which is key to recognizing faces and image depth. Work is also underway on a new generation of chips with significantly higher resolution.
The current implant contains 378 pixels with a width of 100 micrometers, while the new version, currently being tested in preclinical trials, is expected to have up to 10,000 pixels with a size of 20 micrometers. This will allow for a visual acuity of 20/80, and with the help of digital magnification, close to 20/20.
Macular degeneration is the most common cause of vision loss in people over the age of 60. More than 5 million people worldwide suffer from it, and about 1.5 million in Poland. In many cases, the disease leads to complete loss of central vision, making it impossible to function independently.
The study was conducted in collaboration with scientists from Germany, France, the United Kingdom, Italy, the Netherlands, and the United States. The project was funded by, among others, the National Institute for Health and Care Research, Moorfields Eye Hospital NHS Foundation Trust, and University College London Institute of Ophthalmology.
