The PRIMA system is a 2×2mm photovoltaic chip implanted under the retina. It has no battery. No wire. No external power source during use. Specialized glasses project near-infrared light carrying the visual image. The chip converts this light simultaneously into electrical current (power) and spatial pattern (signal). The same photons carry both the energy and the information.
In the PRIMAvera trial across 17 European centers, 81% of 32 patients with advanced dry age-related macular degeneration gained meaningful visual acuity improvement. The average gain was 25 letters — five lines on the eye chart. One patient improved by 59 letters, twelve lines.
The gains are so large because the downstream neural wiring is intact. Dry AMD destroys photoreceptors — the cells that convert light to electrical signals. But the bipolar cells, ganglion cells, and optic nerve that carry the signal to the brain are still there, still functional, still waiting for input. The PRIMA chip replaces only the transducer, not the transmission line. It slots into an existing circuit that was complete except for the first component.
This is why the photovoltaic design matters. A battery-powered implant would need to be larger, require periodic recharging or surgical replacement, and introduce failure modes (battery degradation, lead fracture, infection around percutaneous connectors). The photovoltaic design eliminates all of these by making the implant passive — it does nothing until light arrives, and the light carries everything it needs.
The through-claim: the most elegant interface between technology and biology replaces only the broken component and leaves the rest of the system untouched. The signal path was intact. It just had no input. The smallest possible intervention — adding a transducer — restored function because the system's redundancy was not in the transducer but in everything downstream.