title: Implantation and explantation of an active epiretinal visual prosthesis: 2-year follow-up data from the EPIRET3 prospective clinical trial.
abstract: OBJECTIVE
  The EPIRET3 retinal prosthesis was implanted in six volunteers legally blind from retinitis pigmentosa (RP) and removed after 4 weeks. Two years later, these subjects were re-examined to investigate ocular side effects and potential changes to quality of life.
  
  
  METHODS
  Vision-related quality of life was recorded using the NEI-VFQ-25 questionnaire. Clinical data including interval history, visual acuity, and intraocular pressure were obtained. Anterior and posterior segments of the study eyes were examined and photographed; this included fluorescein angiography and optical coherence tomography (OCT).
  
  
  RESULTS
  Data from five patients could be analysed. Life-quality score was consistent with results obtained at baseline. No unexpected structural alteration could be found in the study eyes. A moderate epiretinal gliosis was present in areas where the epiretinal stimulator had been fixated using retinal tacks. Angiography revealed no leakage or neovascularisation; OCT showed no generalised increase of central retinal thickness.
  
  
  CONCLUSIONS
  Vision-related quality of life is low in patients suffering from end-stage RP. No further deterioration of life quality could however be detected within our monitoring period. Surgery was well tolerated by both patients and their eyes, without adverse events occurring during the follow-up period. Epiretinal gliosis is known to occur with retinal tacks, but seems of no major concern to the integrity of the study eyes. However, it may potentially interfere with functional aspects of active implants. Hence, alternative, possibly biochemical, fixation methods merit further research.
authors.affiliation: Department of Ophthalmology, RWTH Aachen University, Aachen, Germany. johannes.menzelsevering@uk-erlangen.de
authors.forename: J
authors.initials: J
authors.lastname: Menzel-Severing
authors.forename: T
authors.initials: T
authors.lastname: Laube
authors.forename: C
authors.initials: C
authors.lastname: Brockmann
authors.forename: N
authors.initials: N
authors.lastname: Bornfeld
authors.forename: W
authors.initials: W
authors.lastname: Mokwa
authors.forename: B
authors.initials: B
authors.lastname: Mazinani
authors.forename: P
authors.initials: P
authors.lastname: Walter
authors.forename: G
authors.initials: G
authors.lastname: Roessler
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001766:Blindness / Q000209:etiology / Q000503:physiopathology / Q000534:rehabilitation*; D020878:Device Removal; D005260:Female; D005451:Fluorescein Angiography; D005500:Follow-Up Studies; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D019736:Prostheses and Implants / Q000009:adverse effects; D011788:Quality of Life; D012160:Retina / Q000601:surgery*; D012174:Retinitis Pigmentosa / Q000150:complications; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed; D014792:Visual Acuity / Q000502:physiology; D057488:Visual Prosthesis / Q000009:adverse effects