gms | German Medical Science

Objectives: To assess the capability of human subjects visually impaired by geographic atrophy (GA) due to age-related macular degeneration (AMD) to recognize detailed patterns with the PRIMA Bionic Vision System.

Materials and Methods: PRIMA visual prosthesis (Science – previously Pixium Vision, Paris, France) consists of an implantable photovoltaic microchip (2x2 mm in size and 30 µm thick, 378 pixels of 100 µm) and augmented-reality (AR) glasses with a camera, a processing unit and a projection module. Images captured by the camera on the glasses are processed and projected onto the sub-macular implant by near-infrared light (880 nm).

Thirty-eight patients having GA with foveal involvement and visual acuity ≤20/320 were implanted with the chip placed under the macula in the area of GA. Prosthetic visual acuity (VA) was measured with ETDRS charts at 1 meter using preferred electronic zoom.

Results: At 12 months post-op, >75% of the tested subjects showed VA improved by a minimum of logMAR 0.3 (corresponding to 3 lines on ETDRS chart). The mean improvement with the system vs baseline was logMAR 0.5 (5 lines) and the maximum VA gain was logMAR 1.2 (12 lines). Average natural peripheral vision outside the GA lesion did not decrease after implantation.

Discussion: The PRIMA subretinal photovoltaic array can provide detailed monochromatic form vision in GA. The device can be safely implanted under the atrophic macula in GA patients and restore central vision with clinically significant improvement of visual acuity.