PRIMA System: A major step in the battle against GA

The photovoltaic retina implant microarray (PRIMA, Science Corporation) system, an experimental device, restored the central vision in patients with geographic atrophy (GA). The results of a multicenter controlled clinical trial¹ showed that the device resulted in “a significant improvement in visual acuity (VA) from baseline to month 12.” Frank G. Holz, MD, and colleagues reported their results in the New England Journal of Medicine. He is a professor and chairman of the Department of Ophthalmology at the University of Bonn, Bonn, Germany.

This result is a substantial advance in the research to arrest the effects of age-related macular degeneration (AMD), in that GA, the end stage of AMD, results in the death of the photoreceptors and retinal pigment epithelial cells,² which to now was considered an irreversible step down the pathway to blindness.

An editorial by Jacque L. Duncan, MD, professor of ophthalmology and chair of the Department of Ophthalmology, University of California, San Francisco, in the New England Journal of Medicine³ referred to the PRIMA Implant (Science Corporation) as “the first treatment to restore vision” in patients with advanced GA associated with AMD.

The previous advance in this line of research was the FDA approval of 2 drugs (pegcetacoplan, SYFOVRE, Apellis Pharmaceuticals; and avacincaptad pegol, Izervay, Astellas Pharma). These treatments can slow GA progression, but reinjections are required every 1 or 2 months.^4-6 Dr. Holz and colleagues pointed out, “… no approved therapies, investigational approaches, or cell therapies have led to a meaningful improvement in vision.^7-11

“In GA, light is not transduced into electrical signals because of a loss of photoreceptors, which leads to an absolute scotoma (blind spot).^2,3 The PRIMA neurostimulation system replaces the lost photoreceptors,¹² the investigators explained.

The PRIMA system

The PRIMA implant is 2 x 2 mm and 30 μm thick. The system also includes glasses that project near-infrared light to the implant to facilitate vision. The investigators describe the system and its workings as follows: it is “a thin crystalline silicon array comprising 378 photovoltaic pixels that are each 100 μm wide. ^13,14 The array is implanted subretinally within the atrophic lesion. A frame-mounted camera on the PRIMA glasses captures images and projects them, after processing, onto the implant with the use of near-infrared light (wavelength 880 nm). The pixels in the implant convert near-infrared light into electrical pulses to stimulate retinal bipolar cells, which restores the flow of visual information.¹³” In contrast to a prosthesis with wires, this implant enables wireless operation combined with a straightforward implantation technique.^15,16

PRIMA clinical trial

To test the efficacy of the device, the study authors carried out an international, open-label, multicenter, prospective, single-group, baseline-controlled clinical study. All patients had GA and at least 1.2 logarithm of the minimum angle of resolution (logMAR) vision. The patients were evaluated with and without the glasses at 6 and 12 months after the device was implanted.

The primary endpoints were a clinically meaningful visual improvement, which they defined as “≥0.2 logMAR from baseline to month 12 after implantation.” They also recorded the number and severity of serious adverse events related to the implantation procedure or the device through month 12.

What did the results show?

The investigators enrolled 38 participants who underwent implantation of the device; 32 of them were ultimately assessed at the 12-month time point.

“Among the 32 participants who completed 12 months of follow-up, the PRIMA system led to a clinically meaningful improvement in visual acuity from baseline in 26 (81%) (95% confidence interval [CI], 64 to 93; P < 0.001),” Dr. Holz and colleagues reported.

They used multiple imputation to account for the six participants who were not assessed at 12 months; of those, three died, one withdrew, and two were not available for testing. The investigators estimated that 80% (95% CI, 66 to 94; P < 0.001) of all participants would have had a clinically meaningful improvement at 12 months.

The safety analysis showed that 26 serious adverse events occurred in 19 patients. All serious adverse events were related to the implantation procedure alone or to the procedure and the device; no serious adverse event was related to the device alone, the investigators reported.

The most common serious adverse events were ocular hypertension (six events; 23%), peripheral retinal breaks occurred in five participants, three patients had a subretinal hemorrhage during implantation, and full-thickness macular holes in three patients. One patient had a choroidal fold, retinal detachment, and proliferative vitreo-retinopathy that resolved with surgery and a tamponade.

Holz and colleagues concluded, “The data at 12 months in this clinical study showed that the PRIMA subretinal implant restored meaningful central vision in persons with GA due to AMD, thus enabling the performance of visual tasks such as reading and writing. Although no retinal implants have been explanted in humans, the wireless design allows for replacement with higher resolution next-generation implants.^17,18 or implantation of multiple arrays in a tiled pattern at the atrophic area with minimal incision.¹⁹

References

1. Holz FG, Le Mer Y, Muqit MMK, et al. Subretinal photovoltaic implant to restore vision in geographic atrophy due to AMD. N Engl J Med. 2026;394:232-42; DOI: 10.1056/NEJMoa2501396

2. Fleckenstein M, Mitchell P, Freund KB, et al. The progression of geographic atrophy secondary to age-related macular degeneration. Ophthalmology. 2018;125:369-90.

3. Duncan J. Behind the science: restoring vision for patients with AMD and geographic atrophy. N Engl J Med. 2026;394:298-301. Published January 14; DOI: 10.1056/NEJMe2514592

4. Heier JS, Lad EM, Holz FG, et al. Pegcetacoplan for the treatment of geographic atrophy secondary to age-related macular degeneration (OAKS and DERBY): two multicentre, randomised, double-masked, sham-controlled, phase 3 trials. Lancet. 2023;402:1434-48.

5. Patel SS, Lally DR, Hsu J, et al. Avacincaptad pegol for geographic atrophy secondary to age-related macular degeneration: 18-month findings from the GATHER1 trial. Eye (Lond). 2023;37:3551-7.

6. Kang C. Avacincaptad pegol: first approval. Drugs. 2023;83:1447-53.

7. Girgis S, Lee LR. Treatment of dry age-related macular degeneration: a review. Clin Exp Ophthalmol. 2023;51:835-52.

8. Holz FG, Sadda SR, Staurenghi G, et al. Imaging protocols in clinical studies in advanced age-related macular degeneration: recommendations from classification of atrophy consensus meetings. Ophthalmology. 2017;124:464-78.

9. Deng Y, Qiao L, Du M, et al. Age-related macular degeneration: epidemiology, genetics, pathophysiology, diagnosis, and targeted therapy. Genes Dis. 2021;9:62-79.

10. Humayun MS, Clegg DO, Dayan MS, et al. Long-term follow-up of a phase 1/2a clinical trial of a stem cell-derived bioengineered retinal pigment epithelium implant for geographic atrophy. Ophthalmology. 2024;131:682-91.

11. Loewenstein A, Trivizki O. Future perspectives for treating patients with geographic atrophy. Graefes Arch Clin Exp Ophthalmol. 2023;261:1525-31.

12. Lorach H, Goetz G, Smith R, et al. Photovoltaic restoration of sight with high visual acuity. Nat Med. 2015;21:476-82.

13. Palanker D, Le Mer Y, Mohand-Said S, Sahel JA. Simultaneous perception of prosthetic and natural vision in AMD patients. Nat Commun. 2022;13:513.

14. Palanker D, Le Mer Y, Mohand-Said S, Muqit M, Sahel JA. Photovoltaic restoration of central vision in atrophic age-related macular degeneration. Ophthalmology. 2020;127:1097-104.

15. da Cruz L, Dorn JD, Humayun MS, et al. Five-year safety and performance results from the Argus II Retinal Prosthesis System clinical trial. Ophthalmology. 2016;123:2248-54.

16. Schaffrath K, Schellhase H, Walter P, et al. One-year safety and performance assessment of the Argus II Retinal Prosthesis: a postapproval study. JAMA Ophthalmol. 2019;137:896-902.

17. Bhuckory MB, Monkongpitukkul N, Shin A, et al. Enhancing prosthetic vision by upgrade of a subretinal photovoltaic implant in situ. Nat Commun. 2025;16:2820. https://doi.org/10.1038/s41467-025-58084-y.

18. Wang B-Y, Chen ZC, Bhuckory M, et al. Electronic photoreceptors enable prosthetic visual acuity matching the natural resolution in rats. Nat Commun. 2022;13:6627.

19. Lee DY, Lorach H, Huie P, Palanker D. Implantation of modular photovoltaic subretinal prosthesis. Ophthalmic Surg Laser Imaging Retina. 2016;47:171-4.