Abstract
Abstract: :
Purpose: To report on long–term visual function changes in 10 retinitis pigmentosa (RP) patients implanted for 1 to 3 1/2 years with the subretinal Artificial Silicon Retina (ASR) microchip. Methods: An ASR microchip, 2 mm in diameter and 25 um thick, was implanted into the subretinal space 20 degrees from the macula in each of 10 RP patients and followed for up to 42 months. Visual function changes were evaluated objectively by ETDRS letters read, grating acuity, automated visual fields, ERG, OCT, fundus photography and FA, and subjectively by interview and a visual function questionairre. Results: All patients tolerated the ASR microchip implant safely. Electrical function has persisted in all patients, although with some decrease in implant activity, and for 3 1/2 years in the longest implanted patients. Objective and subjective improvements in multiple areas of visual function have also persisted for 3 1/2 years in the longest implanted subjects, although 1 of 3 in this group noted some diminution from the best improvement. The greatest area of objective improvement has been in optotype and grating acuity, and subjectively in contrast perception. Conclusions: The subretinal ASR microchip is well tolerated in RP patients. Persistent improvements of visual function in retina both adjacent to and distant from the ASR implant suggest a persistent neurotrophic benefit of the ASR chip in RP patients.
Keywords: retinal degenerations: hereditary • retina • retinitis