Overview of Progress on the 256+ Channel Boston Retinal Prosthesis

Abstract

 

Purpose:

 

This work is related to the efforts of the Boston Retinal Implant Project to develop a sub-retinal prosthesis to restore vision to the blind. The goal of this presentation is to provide an update of the status of the high-density 256+ channel Boston retinal prosthesis.

 

Methods:

 

The high-density Boston device includes a custom-designed application-specific IC chip and a hermetic Ti case to support 256+ channels. The chip and the package have been tested in vitro, and the entire assembly has been implanted into two mini-pigs, using a unique and newly-developed coiled-cable electrode array. Custom surgical tools were also refined for the new implants. In separate animal studies, the Boston team has also implanted sub-retinal penetrating electrode arrays and compared OCT scans of such arrays to ex vivo histological data.

 

Results:

 

The IC drives electrodes with bi-phasic current pulses when commanded by an external controller and frequency-shift keyed radio transmitter, and human safety protocols for data transmission have been refined. The hermetic package for the device has been welded and leak tested. In vivo implantation with the coiled-cable electrode array reduced the surgical time and improved the degrees of freedom to enter the sub-retinal space. In studies of penetrating electrode arrays, immunohistochemical studies showed modest GFAP and microglial reactions without evidence of glial encasement.

 

Conclusions:

 

Advancements in circuit design, packaging, array design, surgical tools and techniques have put the development of the 256+ channel Boston retinal prosthesis on pace for in vivo validation of function in 2012.  

 

Keywords: retina • neuro-ophthalmology: cortical function/rehabilitation • quality of life