To determine the safety and efficacy of the artificial silicon retina(ASR) microchip implanted in the subretinal space to treat vision loss fromretinitis pigmentosa.
The ASR microchip is a 2-mm-diameter silicon-based device that containsapproximately 5000 microelectrode-tipped microphotodiodes and is powered byincident light. The right eyes of 6 patients with retinitis pigmentosa wereimplanted with the ASR microchip while the left eyes served as controls. Safetyand visual function information was collected.
During follow-up that ranged from 6 to 18 months, all ASRs functionedelectrically. No patient showed signs of implant rejection, infection, inflammation,erosion, neovascularization, retinal detachment, or migration. Visual functionimprovements occurred in all patients and included unexpected improvementsin retinal areas distant from the implant.
Main Outcome Measures
Subjective improvements included improved perception of brightness,contrast, color, movement, shape, resolution, and visual field size.
No significant safety-related adverse effects were observed. The observationof retinal visual improvement in areas far from the implant site suggestsa possible generalized neurotrophic-type rescue effect on the damaged retinacaused by the presence of the ASR. A larger clinical trial is indicated tofurther evaluate the safety and efficacy of a subretinally implanted ASR.