The following transcript has been edited for clarity.
Good afternoon. I'm Ehsan Rahimy, MD. I'm a practicing vitreoretinal specialist out of the San Francisco-Palo Alto Bay Area. I’m at the Palo Alto Medical Foundation and also at Stanford. I'm here today at the American Academy of Ophthalmology meeting 2026 in New Orleans. It's been a wonderful meeting so far.
Yesterday, I presented extended 36-month efficacy and safety data on the PRIMA subretinal prosthetic chip implant. And I'm excited to share the take-home findings from that study with you here today. This is very exciting technology. Just very briefly, for those who are not familiar, this is essentially a subretinal photovoltaic chip implant. It has a very thin profile: 2x2 mm, 30 µm thick, 378 pixels. It’s not attached to any wires. There’s no battery. It’s inserted surgically via a subretinal approach with standard pars planavitrectomy. Then a patient wears augmented reality glasses over it with a miniature camera that records a live feed. And this visual data is converted into pulse near-infrared light. That infrared light is transmitted through the eye, and that’s what these individual pixels on the chip are tuned for.
So imagine microscopic solar panels rather than being tuned for sunlight, they’re actually being tuned for infrared light. And what this chip is doing, because it’s subretinal, is replacing the function of lost photoreceptors. So photovoltaic means “light to energy,” basically. Light’s being absorbed; it's being converted to an electrical current, stimulating the bipolar cells and the ganglion cells, essentially utilizing the native signaling structure of the retina.
Now, 12-month efficacy data has already been presented on this. This was done in Europe at over 17 clinical sites. There are 38 patients enrolled in this trial. It's called the PRIMAvera trial. They have advanced end-stage geographic atrophy. The average visual acuity for participating patients was the equivalent of 20/460 to begin, just to give you some context into how much vision loss we're talking about for this group of patients. With proper training with this device, 12 months after surgery, these patients were gaining a mean of 25 ETDRS letters. At 36 months, when I presented, that had extended to a mean of about 30 ETDRS letters, which is very compelling.
The part a lot of colleagues are curious about is, because it’s a surgical procedure—this is subretinal surgery—what is the safety profile like? And that was the other aspect of the presentation. There were 29 serious adverse events (SAEs) that were reported during the course of the study. The vast majority of them, 83% of them, took place in the first 6 months after surgery. This is to be expected again in line with complex vitreoretinal surgery doing subretinal incisions and insertion of a device. The key thing to take home is, all of these incidents were managed, and having an SAE did not compromise a patient’s natural vision, meaning with the device off. They were no worse off than their existing vision, or how their fellow eye performed over the 3-year period.
Equally important is that experiencing an SAE did not preclude a patient from still potentially gaining significant vision. We saw almost two-thirds of those patients who experienced an SAE in the study were still able to achieve at least 15 letters of ETDRS visual gain. So I thought that was very exciting.
In summary, we presented 36-month efficacy and safety data on the PRIMA chip implant. It’s still working well in these eyes. The patients have adapted and adjusted to how to best use it. Many of the patients are incorporating it into their routine daily lives beyond just being able to read letters or numbers. The safety profile is manageable. It’s front-loaded within the first 6 months, which is to be expected after any surgery. Most importantly, experiencing an SAE is manageable, but it also does not restrict the patient from still potentially experiencing transformative visual acuity gains.
We’re very excited to see where this technology goes. Thank you for tuning in today. RP