The implant, protected by a long steel tube, was advanced through a retroauricular incision to the lateral orbital rim and guided inside the orbit to the surface of the eyeball ([21 (link)]; figure 2a,b,e). The silicone cable (figure 2a) was implanted subperiostally beneath the temporal muscle. The polyimide foil was then protected by a silicone tube and guided from the lateral orbital rim, where it was fixed, to the equator of the eye. Subsequently pars plana vitrectomy was performed. A localized retinal detachment was created by saline injection in the upper temporal quadrant above the planned scleral and choroidal incision area. After preparation of a scleral flap, the implant was advanced ab externo transchoroidally along a guiding foil into the subretinal space until it reached the preoperatively defined position ([22 ]; see electronic supplementary material, chapter 2d). Although putting a chip directly under the fovea has not turned out to be a surgical problem we had abstained in initial patients from placing the chip under the macula, but asked to place the chip closer and closer to the foveola as the surgical learning curve improved. Silicone oil was then injected into the vitreous cavity to support retinal reattachment. No serious adverse events were noted during the course of the study. For post-operative observations and consideration on surgical safety see electronic supplementary material, chapter 2f).

Implant position in the body. (a) The cable from the implanted chip in the eye leads under the temporal muscle to the exit behind the ear, and connects with a wirelessly operated power control unit. (b) Position of the implant under the transparent retina. (c) MPDA photodiodes, amplifiers and electrodes in relation to retinal neurons and pigment epithelium. (d) Patient with wireless control unit attached to a neckband. (e) Route of the polyimide foil (red) and cable (green) in the orbit in a three-dimensional reconstruction of CT scans. (f) Photograph of the subretinal implant's tip at the posterior eye pole through a patient's pupil.

Free full text: Click here