gms | German Medical Science

Background: The feasibility of implantation surgery of large epiretinal stimulators (VLARS = very large arrays retinal stimulator) shall be demonstrated. The clinical aim is to provide artificial vision with enlarged visual fields in patients with retinal dystrophies like Retinitis pigmentosa.

Methods: Polyimide stimulation foils with a diameter of 12.5 mm have been fabricated for implantation. Each stimulation foil contains a central field of electrodes and further electrodes for peripheral stimulation. Openings for retinal tack fixation are embedded paracentrally and in the periphery of the stimulator. Implantation is performed in pig’s eyes including lens removal, vitrectomy and the implantation via a corneal incision.

Results: Following lens removal by phacoemulsification and three-port vitrectomy, a decaline bubble is installed into the vitreous cavity. Via a “clear-cornea”-incision the folded stimulator is inserted into the eyeball and positioned onto the decaline bubble. Following aspiration of the decaline bubble the stimulator is lowered and positioned epiretinally at the posterior pole. The stimulator shows an overall flat contact to the retinal surface. The implantation is finished by fixation using retinal tacks.

Conclusion: Our experiments demonstrate the feasibility of implantation surgery of large electrode arrays for retinal dystrophies. Long term implantation for biocompatibility testing as well as stimulation experiments for the generation of cortical activation in animal experiments will follow.