Surgical Methods for Implantation of Dual Sub-Retinal Electrode Arrays Into One Minipig Eye

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 specific purpose of this presentation is to develop a safe surgical method to implant two sub-retinal electrode arrays in the same eye, which could conceivably be used to provide central and peripheral vision.

 

Methods:

 

7 Yucatan miniature pig eyes were implanted with Inactive, HD Microsystems PI-2611 polyimide arrays using ab externo approach. Two array designs were used. The ‘small’ array was 1.510 mm x 101.5 mm x 15 µm, with 15 Iridium Oxide electrodes (400 microns in diameter). The ‘large’ array was 5 mm in diameter and 16 microns thick, with 100 Iridium Oxide electrodes (200 microns in diameter). In 2 survival surgeries and in one acute surgery, a single scleral flap was created temporally 8mm posterior to the limbus for insertion of both arrays. In 4 acute surgeries, nasal and temporal flaps were created 8 mm posterior to the limbus to insert each array separately. Arrays were inserted with the help of a guide.

 

Results:

 

Among the 5 acute surgeries, a large array and a small array were successfully implanted in one eye through a single scleral flap; two small arrays were successfully implanted in another eye through two, separate scleral flaps. Two small arrays were successfully implanted in the other 3 eyes via two slceral flaps, while large arrays were only partially sub-retinal. Among the 2 survival surgeries with a single scleral flap, a large and small array were successfully implanted, while the second surgery failed due to retinal incarceration secondary to choroidal rupture during cauterization.

 

Conclusions:

 

A large array and a small array, or two small arrays could be implanted into the sub-retinal space of one minipig eye. Dual- array implantation has the potential to provide central vision through the small array and wider visual field through the large array. More experiments will be performed to develop this procedure.  

 

Keywords: retina