Surgical Implantation of Newly Designed Subretinal Implant in Minipig Eyes

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. This presentation summarizes the latest generation Boston retinal implant and its surgical results in minipig eyes.

 

Methods:

 

The latest generation Boston retinal implants were implanted into 3 minipig eyes via an ab externo method to study in vivo biocompatibility. Our inactive implants contain 2mm wide secondary power and data receiving coils, a 2.4mm thick hermetic case and a parylene coated 29 µm-thick, 4mm wide polyimide-based flexible electrode arrays. The spherically-molded coil has a inner diameter of 19.4 mm and a thickness of 0.18 mm. To prevent excessive bleeding, "controlled" systemic hypotension was introduced during insertion. A local retinal detachment was created after vitrectomy. The coils were sutured around the cornea and the hermetic cases were sutured onto sclera nasally. Electrode arrays were placed into subretinal space temporally with an ab externo method. Conjunctiva and the tenon were closed over the implant.

 

Results:

 

All 3 inactive implants were successfully implanted into 3 minipig eyes. One electrode array was implanted into the subretinal space. One electrode array was partially implanted into the subretinal space. The other surgery did not include the array implantation procedure. Two out of the 3 pigs showed very good tolerance of the device. One pig experienced erosion of the conjunctiva by the device.

 

Conclusions:

 

Our latest generation Boston retinal implant has a better biocompatibility in Yucatan minipig eyes with our modified surgical methods. More experiments will be done to improve the long term biocompatibility of our device.  

 

Keywords: vitreoretinal surgery • retinal detachment • neuro-ophthalmology: cortical function/rehabilitation