title: Acute electrical stimulation of the human retina with an epiretinal electrode array.
abstract: OBJECTIVE
  To determine the threshold charges needed for eliciting visual perceptions through acute electrical stimulation of the human retina in patients suffering from retinitis pigmentosa, using an epiretinal microelectrode array.
  
  
  METHODS
  In a multicentre study, 20 patients (average age 55 years) with visual acuities ranging from 4/200 to no light perception were included. The stimulation procedure was performed during a pars plana vitrectomy, for a maximum of 45 min, by using a microcontact film with IrO(x) electrodes connected by cable to a current generator. After repeated stimulation and threshold charge determination, the microelectrode array was removed.
  
  
  RESULTS
  Nineteen of 20 patients stated in the postoperative interviews that they experienced one or more visual perceptions with close time correlation to single stimulation events. Minimum threshold charges needed to generate visual perceptions could be measured and verified in 15 patients. The charge level ranged from 20 to 768 nC with single or multiple electrodes. One patient suffered a retinal detachment during the procedure; this patient's retina was successfully reattached. There were no further adverse reactions observed during the 3-month follow-up.
  
  
  CONCLUSIONS
  Acute epiretinal stimulation of the human retina, using a microelectrode array, can elicit visual perceptions in blind patients with retinitis pigmentosa.
authors: Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. m.keserue@uke.uni-hamburg.de
authors: Matthias
authors: M
authors: Keserü
authors: Matthias
authors: M
authors: Feucht
authors: Norbert
authors: N
authors: Bornfeld
authors: Thomas
authors: T
authors: Laube
authors: Peter
authors: P
authors: Walter
authors: Gernot
authors: G
authors: Rössler
authors: Michaela
authors: M
authors: Velikay-Parel
authors: Ralf
authors: R
authors: Hornig
authors: Gisbert
authors: G
authors: Richard
mesh_terms: D000328:Adult; D000368:Aged; D004599:Electric Stimulation Therapy; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D008297:Male; D008839:Microelectrodes; D008875:Middle Aged; D012160:Retina / Q000502:physiology*; D012162:Retinal Degeneration / Q000503:physiopathology / Q000628:therapy*; D012684:Sensory Thresholds / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology; D014794:Visual Fields / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*