Abstract
Purpose :
To evaluate the central prosthetic vision with the photovoltaic subretinal implant activated by augmented-reality glasses and simultaneous perception of the natural peripheral vision in patients with geographic atrophy.
Methods :
Five patients with visual acuity ≤20/400 due to geographic atrophy of at least 3 optic discs diameters and no foveal vision have been implanted with a wireless photovoltaic chip (PRIMA, Pixium Vision) of 2x2mm in size, 30µm in thickness, containing 378 pixels of 100µm in width. Each pixel in the implant converts pulsed near-infrared light (880nm) projected from video glasses into electric current to stimulate the nearby neurons in the inner nuclear layer of the retina. Prosthetic acuity was assessed using electronic magnification of 1, 2, 4 and 8. Simultaneous perception of central prosthetic and peripheral natural vision was evaluated under room lighting.
Results :
In all patients, chip implanted under the macula remains stable and functional, with a follow-up extending now up to 3 years. No decrease in natural eccentric visual acuity was observed in any of the study eyes. All 5 patients perceive white-yellow patterns with adjustable brightness, in retinotopically correct locations within previous scotomata. All 4 patients with subretinal placement of the chip achieved acuity without zoom in the range of 20/438 – 20/564, corresponding to the average of 1.17±0.13 implant pixels. With electronic magnification of up to a factor of 8, patients demonstrated acuity in the range of 20/63-20/98. Under room lighting, patients could simultaneously use prosthetic central vision and the remaining peripheral vision in the operated eye and in the fellow eye.
Conclusions :
Wireless chip PRIMA implanted under the atrophic macula in patients with geographic atrophy remains stable and functional during the 2-3 years of follow-up. The implant provides central visual perception with acuity close to the single pixel size of the photovoltaic array. Augmented reality glasses enable simultaneous perception of the central prosthetic and natural peripheral vision under room lighting, while electronic zoom provides significantly higher resolution.
This is a 2021 ARVO Annual Meeting abstract.