Purchase this article with an account.
K Shinoda, F Gekeler, E Eckert, E Zrenner, V-P Gabel, K Kobuch; Ab Externo-Implantation, -Explantation and Postoperative Follow Up of Subretinal Electronic Devices . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4471.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: The development of electronic devices for restoration of vision with either epi- or subretinal implants has come to a stage, where human trials are focused on. A safe surgical technique for implantation, which also enables explantation and a possible exchange of an implant after an extended period of time, is mandatory. A novel technique, an ab externo subretinal implantation and explantation, is demonstrated here in rabbit eyes. Method: Polyimid-foil-strips (2mmx20mm) with a microchip placed on the inner end were pushed in the subretinal space of rabbit eyes (n=4) through a transscleral, transchoroidal incision. The external part of the foil was submerged under the sclera. Four weeks later, the subscleral part of the foil was lifted outside via a conjunctival and scleral incision. The foil strip with the chip was pulled out of the subretinal space from the outside under transpupillary visual control with the help of a contact lens. After removal of the implant, the eyes were observed for another 2 weeks. Then the operated eyes were enucleated for histology. Results: The transchoroidal implantation of the soft polyimid-foil-implant was possible by using an extra foil as a slide rail. The implants were tolerated well, without any inflammatory reaction. The retina remained stable with the small ribbon-implant in the subretinal space. Explantation of the device could be performed safely after 4 weeks without an intraocular procedure and without causing damage to the implant. After explantation (2 weeks), the eyes remained well preserved without proliferative reaction and retinal detachment. Histology showed in general well preserved RPE and retinal structures above and under the implant, but atrophic alterations of the avascular rabbit retina was evident in some areas. Conclusion: This surgical technique may demonstrate a safe procedure for a temporary implantation or optional exchange of a subretinal device without major intraocular surgery, which allows certain variability concerning the final design of the prosthesis.
This PDF is available to Subscribers Only