title: Angiographic findings following tack fixation of a wireless epiretinal retina implant device in blind RP patients.
abstract: BACKGROUND
  The fixation of polyimide stimulator foils as the basic substrate of epiretinal prostheses by using retinal tacks may cause retinal or choroidal alterations such as retinal proliferations or choroidal neovascularizations. During the prospective trial for the semichronical testing of a wireless intraocular retinal implant (EPIRET3) we investigated alterations in angiographic findings during implantation and after explantation of the device, to detect potential vascular pathologies at the fixation site or elsewhere.
  
  
  METHODS
  As the final step of the implantation surgery in six blind patients, the stimulator was placed on the retinal surface using retinal tacks. For the detection of possible morphological or vascular alterations committed by the implant fluorescein angiography (FA) was performed 1 day before and 4 weeks after implantation surgery, as well as at the final visit 5 months after explantation.
  
  
  RESULTS
  Following implantation surgery funduscopy and FA did not reveal any evidence of either vascular pathologies or choroidal neovascularisations (CNV), in addition, no cystoid macular edema (CME) occurred after 4 weeks. At the 6-month follow-up visit, we found a mild epiretinal gliosis formation in four patients. In one patient a retinal break occurred during explantation, requiring a temporary silicone-oil endotamponade. At the final visit, we observed a focal proliferative vitreoretinopathy (PVR) reaction without activity, while there was no evidence for a CNV formation in that area.
  
  
  CONCLUSIONS
  The FA findings confirm our previous results on the safety of the EPIRET3 system, which was tolerated in all patients but revealed a certain risk profile in regard to the stimulator fixation. While there was no evidence for newly occurred CME or CNV during the follow-up visits, nevertheless gliosis or even PVR reaction at the tack's fixation site suggests the need to develop alternative fixation procedures of epiretinal stimulators.
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany. groessler@ukaachen.de
authors.forename: Gernot
authors.initials: G
authors.lastname: Roessler
authors.forename: Thomas
authors.initials: T
authors.lastname: Laube
authors.forename: Claudia
authors.initials: C
authors.lastname: Brockmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Kirschkamp
authors.forename: Babac
authors.initials: B
authors.lastname: Mazinani
authors.forename: Johannes
authors.initials: J
authors.lastname: Menzel-Severing
authors.forename: Norbert
authors.initials: N
authors.lastname: Bornfeld
authors.forename: Peter
authors.initials: P
authors.lastname: Walter
mesh_terms: D001766:Blindness / Q000534:rehabilitation / Q000601:surgery*; D020256:Choroidal Neovascularization / Q000209:etiology / Q000517:prevention & control; D020878:Device Removal; D004567:Electrodes, Implanted / Q000009:adverse effects; D005240:Feasibility Studies; D005451:Fluorescein Angiography; D005500:Follow-Up Studies; D005911:Gliosis / Q000209:etiology; D006801:Humans; D010211:Papilledema / Q000209:etiology / Q000517:prevention & control; D011446:Prospective Studies; D019919:Prosthesis Implantation / Q000009:adverse effects / Q000379:methods*; D012160:Retina / Q000601:surgery*; D012174:Retinitis Pigmentosa / Q000534:rehabilitation / Q000601:surgery*; D059015:Wireless Technology / Q000295:instrumentation*