Subretinal Electrode Implantation in the P23H Rat: An Experimental Model

Abstract

Purpose: : Within the paradigm of the development of a subretinal prosthesis, to design and implant a subretinal electrode and develop a stable montage in the dystrophic P23H rat in vivo. The purpose of this effort was to then obtain electrical impedance, stimulation and recording data in a retinal dystrophy model akin to human retinitis pigmentosa.

Methods: : We developed a technique for implanting a custom–designed electrode–polyimide platform into the subretinal space of the retinal dystrophic rat and stabilising the distal extremity of the cabling onto the rat cranium.

Results: : In vivo indirect ophthalmoscopy, SLO imaging and histology demonstrated adequate subretinal placement of the prosthesis ‘head’, reasorbption of the surgically induced retinal detachment which occurred at the time of surgery and the absence of major tissue reactions. The cranial montage of the extraocular portion of the system was evaluated and found to be stable and well–tolerated.

Conclusions: : This study demonstrates that a retinal implant can be introduced into the subretinal space of the P23H rat with a stable external connector for repeatable electrical measurements and stimulation. This in vivo model should therefore allow us to acquire data for prosthetic protoypes in larger mammals.

Keywords: retina • low vision • degenerations/dystrophies