PRIMA Retinal Implant Restores Reading Ability in 81 Percent of Blind Patients, NEJM Finds
The PRIMA wireless retinal implant restored reading ability in 81 percent of blind AMD patients in a landmark NEJM trial — the first device to restore true form vision.
Overview
A wireless retinal implant has restored the ability to read and recognize faces in the majority of patients who had lost central vision to advanced age-related macular degeneration (AMD), according to results from the international PRIMAvera clinical trial published in the New England Journal of Medicine. The findings mark the first time any device has demonstrated functional form vision — as opposed to simple light sensitivity — in a large group of blind patients.
The PRIMA system, developed by Stanford ophthalmology professor Daniel Palanker and commercialized by Science Corporation, consists of a 2-by-2 millimeter photovoltaic chip implanted beneath the retina and a pair of specialized glasses fitted with a miniature camera. The camera transmits images to the chip via near-infrared light, and the chip converts that light into electrical pulses that stimulate surviving retinal cells, bypassing the degenerated photoreceptors.
What We Know
The PRIMAvera trial enrolled 38 patients aged 60 and older with geographic atrophy — the advanced, “dry” form of AMD — across 17 clinical sites in five European countries. Of the 32 participants who completed one year of follow-up, 26 (81 percent) achieved a clinically meaningful improvement in visual acuity of at least 10 letters on a standard ETDRS eye chart, according to the NEJM study. The average gain was 25.5 letters, equivalent to more than five lines, and one patient improved by 59 letters — nearly 12 lines.
Equally significant, 27 of 32 participants regained the ability to read within one year, as detailed in Stanford Medicine’s coverage of the trial. With digital image enhancements such as zoom and contrast adjustment available through the glasses, some patients achieved vision acuity equivalent to 20/42. Natural peripheral vision — which the implant does not replace — remained stable throughout the trial.
Adverse events were primarily procedural: 26 serious adverse events occurred across 19 participants, with 95 percent of those events resolving within two months of surgery. No patient experienced long-term loss of natural peripheral vision as a result of the implantation.
An accompanying NEJM editorial described the PRIMA system as “the first treatment to restore vision in persons with advanced geographic atrophy,” a designation that sets it apart from prior devices that produced only rudimentary light perception.
What We Don’t Know
The PRIMAvera trial was conducted in Europe; broader outcomes data from more diverse populations is not yet available. The follow-up period for most participants was 12 months, and the durability of restored vision over multiple years remains to be established in longer studies.
Science Corporation has submitted a CE Mark application in Europe, with anticipated availability in 2026. In the United States, an FDA approval process is underway, but no submission date or timeline has been disclosed. It is not yet clear what the device will cost or whether insurers will cover it.
The system also requires patients to wear the specialized glasses at all times to use the prosthetic vision, which may limit practical use in certain environments. Long-term effects of chronic near-infrared illumination on any surviving photoreceptors have not been fully characterized.
Analysis
Geographic atrophy affects an estimated 1 million Americans and over 8 million people worldwide, according to Science Corporation’s reporting on the trial. Until 2023, there were no approved treatments capable of slowing the disease; the first two anti-complement therapies cleared by the FDA modest the rate of lesion growth but do not restore lost vision. PRIMA addresses a fundamentally different therapeutic goal: rehabilitation of function that has already been lost.
Dr. Palanker, who conceived the device’s photovoltaic architecture in 2005, described the result in Stanford Medicine’s coverage as a departure from the prior state of the art: “All previous attempts resulted in basically light sensitivity, not really form vision. We are the first to provide form vision.”
The distinction matters clinically. The Argus II retinal prosthesis and similar earlier devices produced low-resolution phosphene patterns that allowed patients to detect edges and motion but not to read text or recognize faces. The PRIMA system’s higher pixel density — 100 micron pixels across the 2-millimeter array — and its photovoltaic wireless architecture appear to enable a qualitatively different level of visual function.
Whether PRIMA can scale commercially and reach the broad population of AMD patients will depend on regulatory clearances, manufacturing capacity, and pricing decisions that remain to be made. But the PRIMAvera trial results establish, for the first time in a peer-reviewed, multi-center study, that restoring functional central vision after AMD is possible.