Abstract
Abstract: :
Purpose: To develop methods for subretinal implantation and fixation of microfabricated electronic devices, and to assess the biocompatibility of materials. This is a preliminary study of the feasibility of implanting polyimide-based material in the subretinal space. Methods: : Strips of polyimide 0.5 by 5 mm and 10 microns thick were implanted in the subretinal space in one eye of each of 3 Yucatan minipigs, after pars plana vitrectomy was performed, and a local retinal detachment created by injection of subretinal balanced salt solution via a Lambert cannula. Polyimide was placed through the retinotomy, which was held open with a lighted pic. A subtotal air/fluid exchange was performed. ERGs were done pre-op and at post-operative intervals. Histopathology was performed at 3 months. Fundus photography was performed at intervals. The protocol for implantation studies was approved by the Animal Care Committee of MIT, where the work was performed. Results: Small amounts of bleeding occurred from the retinotomy sites intraoperatively and/or postoperatively. Vitreous and small subretinal hemorrhages cleared slowly. The local retinal detachments resolved rapidly, and the polyimide remained in a stable subretinal position in all eyes. ERG amplitudes were reduced at one week, but then remained stable or showed some recovery. Histopathology is pending. Conclusion: Thin polyimide strips remain in a stable location after subretinal implantation through a retinotomy. There is no gross inflammatory reaction, fibrous proliferation, or retinal pigment epithelial proliferation. Histologic examination of specimens is pending. The results are consistent with work previously reported by Chow’s group and Zrenner’s group.
Keywords: 554 retina • 316 animal model