Intraocular Camera for Retinal Prostheses

Abstract

Purpose: : To advance the design of a miniaturized video camera for use in conjunction with an epiretinal microelectrode array in support of a surgically–implantable retinal prosthesis.

Methods: : Previously, the optimal placement and device limitations of a surgically implantable intraocular camera were investigated. This new design utilizes the existing corneal lens and aqueous humor in conjunction with an aspherical lens to allow for improved field flattening at the detector plane, thus providing imaging characteristics that are matched to the degree of pixellation required by current and envisioned epiretinal microelectrode arrays. Additional visual psychophysics techniques were employed to reveal optimal pixellization and image pre– and post–processing requirements, yielding relaxed camera design constraints. The entire imaging device is designed to be surgically placed within the crystalline lens sac following a vitrectomy procedure similar to that commonly used for cataract surgery. This 3rd generation system exhibits reduced camera mass, advanced packaging technologies, reduced electrical/thermal power dissipation, and a feasible haptic design, all of which are critical elements for a human implantable intraocular camera.

Results: : A third–generation prototype intraocular camera (6 mm x 4 mm) was constructed and tested building upon previous work. This low mass prototype was sealed and will be surgically implanted in a canine eye for acute testing. Total camera mass, packaging, thermal, and haptic design issues are discussed.

Conclusions: : The replacement of an extraocular (head–mounted) camera with an advanced intraocular camera for retinal prostheses is feasible, providing natural image acquisition using eye movement.

Keywords: retina • optical properties