gms | German Medical Science

Purpose: To develop a surgical technique for epiretinal implantation and attachment of retinal prosthetic devices, while considering procedure time, patient recovery, and precision of implantation.

Methods: Nano-Retina dummy implant made of silicon and glass was used to develop the surgical procedure in the domestic pig. Anterior chamber approach through the limbus and a pars-plana approach were tested. Animal behavior, fundus examination and histology were used to evaluate long-term retinal response.

Results: The anterior chamber approach was found to be preferable to the pars-plana approach due to the fairly large incision that was required for insertion of this relatively small implant. The procedure begins in standard anterior capsulotomy ,lens aspiration and posterior capsulotomy. Partial pars-plana 23G vitrectomy is then performed and the implant is inserted through the anterior chamber via the opening in the posterior capsule, followed by in the bag intraocular lens implantation. The remaining vitreous cushions the implant and is gradually removed to place the implant gently on the retina. The surgery was completed within one hour. Chronic implantations to evaluate long-term reaction of the eye to the implant will be described as well as different modes of attachment of the implant to the retina.

Conclusions: Implantation surgery through the limbus, an expansion of the commonly performed cataract surgery followed by lens implantation, was found to be suitable and efficient for epiretinal implantations of retinal prosthesis. Furthermore, patients who undergo vitreal procedures generally develop a cataract within months and would require lens replacement. This procedure circumvents this additional surgery.