Retinal stimulation microchip shows encouraging outcomes in severe dry AMD

The first-in-human trial assessing the safety and efficacy of the PRIMA photovoltaic retinal stimulation microchip for severe central vision impairment due to dry age-related macular degeneration (AMD) showed positive outcomes at 4 years. “The trial data show that the implantation of PRIMA is feasible and well tolerated in all five study participants, with no reduction of natural peripheral visual function after 48 months,” Pixium Vision said in a press release. Patients experienced a clinically meaningful visual acuity improvement of up to eight lines on a vision chart and were able to recognize letters and sequences of letters. 

The PRIMA retinal prosthesis is designed to be implanted under the fovea, a part of the retina responsible for sharp, central vision, with a minimally invasive procedure and includes a 2 mm wide and 30 µm thick photovoltaic neurostimulation microchip carrying 378 electrodes of 100 µm in diameter. Each pixel of the implant independently converts light projected from transparent augmented-reality glasses into electric current, stimulating the inner retinal cells and restoring visual perception within the central scotoma (blind spot). 

“Unlike the current and potential pharmacological treatments for geographic atrophy, which aim to slow the growth of atrophic lesions [regions of dead cells] without functional improvement in visual acuity, the PRIMA study results demonstrate restoration of central vision in the former scotoma,” Frank G. Holz, MD, PhD, scientific coordinator of the study, said in the release. “At the 4-year timepoint, the mean gain was 32 letters, which corresponds to an improvement of logMAR 0.6 (six lines) and should be considered clinically meaningful for patients with geographic atrophy with foveal involvement secondary to AMD.”

Note that according to Pixium Vision’s website, a court rejected an offer by Neurotech to buy Pixium’s assets and placed Pixium in liquidation with immediate effect and cessation of activities. Prixium closed as of January 31, 2024.

Source: Healio Ocular Surgery News, November 16, 2023; see source article