Session Title: Free Paper Session 18: New Drug & Treatment Technology
Session Date/Time: Saturday 09/09/2017 | 14:30-16:00
Paper Time: 15:48
Venue: Room 120
First Author: : Y.Le Mer FRANCE
Co Author(s): : J. Hubschman R. Hornig A. Hoffman H. Lorach D. Palanker D. McCreery
To demonstrate the safety of retinal stimulation by the wireless PRIMA photovoltaic sub-retinal implant in cats.
Eye Care for Animals, Pasadena, USA
The photovoltaic retinal prosthesis, PRIMA, is composed of photovoltaic arrays for sub-retinal stimulation, activated via video goggles. The silicon chips, of 1 to 2 mm in diameter and 30um in thickness, consist of pixels with integrated photodiodes and stimulation electrodes. Photodiodes convert pulsed near-infrared illumination into electric current, which is injected into the tissue via a pair of concentric electrodes in each pixel. In this study, PRIMA arrays have been implanted into the left eye of 15 cats under general anesthesia following IACUC guidelines. The surgical procedures included 23 G vitrectomy, detachment of the posterior hyaloid, creation of a retinal bleb, implantation of the PRIMA array into the sub-retinal space, photocoagulation of the retinotomy and gas tamponade. The first four cats were used to establish the surgical method. Nine cats were then used to assess the safety of stimulation. Two additional cats were used to assess erosion of the implant. After humane euthanasia, the 11 eyes were prepared for histological examination.
After establishing the surgical method, all surgeries have been successful. The postoperative OCT and fundus examinations confirm correct sub-retinal position of the implant, without migration or evidence of adverse events. Retinal histopathology evaluation did not show inflammatory cells or necrosis. The ganglion cells and bipolar cells were well preserved. Implant functionality was validated using VEP recordings in 5 animals, which confirmed that the implants were functioning as expected. The explanted devices showed no detrimental effects after 102 days-long implantation.
Subretinal implantation of PRIMA arrays is feasible. The devices can be operated without adverse effects to the retinal bipolar and ganglion cells or any other safety concerns