A groundbreaking wireless implant has shown promise in restoring central vision for individuals suffering from age-related macular degeneration (AMD), a condition that leads to irreversible vision loss. In an international clinical trial, the PRIMA (photovoltaic retina implant microarray) system enabled 27 out of 32 participants to read again after one year of follow-up.
AMD is the leading cause of untreatable blindness among older adults. The advanced stage, known as geographic atrophy, results in the progressive loss of light-sensitive photoreceptors located at the center of the retina. This degeneration prevents light from being converted into electrical signals, leading to significant vision impairment.
The PRIMA system compensates for the lost photoreceptors through a two-part mechanism. The implant consists of a 2 x 2 mm microarray containing 378 photovoltaic pixels, while accompanying PRIMA glasses are equipped with a video camera that captures images. After processing, these images are projected onto the implant using near-infrared light. The implant”s pixels then convert the light into electrical pulses, which help restore visual information to the brain. Patients can manipulate the glasses to adjust the focus and zoom of the images they see.
The clinical trial, spearheaded by Frank Holz from the University of Bonn, included 38 participants across 17 medical facilities in five European nations. Each participant suffered from geographic atrophy due to AMD in both eyes, with significant central vision loss in the study eye, limiting them to peripheral vision only.
Approximately one month following the surgical placement of the 30 μm-thick PRIMA array into one eye, the patients began utilizing the glasses. They received training to interpret the visual signals generated by the implant, with their visual acuity improving through months of practice.
After a year, 27 of the 32 patients who completed the study were able to read letters and words, with some even capable of reading complete pages from a book. Additionally, 26 participants exhibited clinically significant improvements in visual acuity, with an average increase of five lines on a standard eye chart, and one individual achieving an extra 12 lines.
While 19 participants reported side effects from the surgical procedure, 95% of these adverse events resolved within two months. Notably, the implantation of the PRIMA device did not adversely affect the patients” peripheral vision. The researchers emphasized that the infrared light utilized by the implant remains invisible to the remaining photoreceptors outside the damaged area, allowing patients to retain their natural peripheral vision alongside the restored central vision.
“Before receiving the implant, it was like having two black discs in my eyes, with the outside distorted,” shared Sheila Irvine, a participant from Moorfields Eye Hospital in the UK. “I was an avid bookworm, and I wanted that back. There was no pain during the operation, but you”re still aware of what”s happening. It”s a new way of looking through your eyes, and it was dead exciting when I began seeing a letter. It”s not simple, learning to read again, but the more hours I put in, the more I pick up. It”s made a big difference.”
The PRIMA system, initially developed by Daniel Palanker at Stanford University, is now being advanced and manufactured by Science Corporation. Following these encouraging results published in the New England Journal of Medicine, the company has sought clinical use authorization in both Europe and the United States.
