Abstract
Purpose: :
To evaluate the long term local safety and performance of the first wireless retinal implant system in blind patients with retinitis pigmentosa and to exclude severe damage to ocular tissues caused by the implant.
Methods: :
In a prospective study, 3 subjects with a visual acuity of light localization or less recieved an epiretinal implant. Surgical fixation of the implant was realised by only one especially designed retinal tack. The postoperative follow-up is up to 30 months. ICG and fluorescein angiograms (HRA, Heidelberg Engineering) and OCT investigations (Stratus and Cirrus OCT, Carl Zeiss Meditec) were performed on predefined follow-up examinations. Angiograms and OCT were examined and compared looking for vascular changes, changes in tissue integrity or damage caused by the implant.
Results: :
Angiograms and fundus photographs revealed a stable positioning of the electrode array over the whole follow-up period. Fluorescein angiograms showed no signs of vascular leackage or tissue proliferation. OCT data proved a close proximity between the retina and the electrode film. Some OCT show slight retinal compression. No retinal tissue damage was observed.
Conclusions: :
ICG, FAG and fundus photographs document a good tolerability of the implantes electrode array for nearly 3 years. OCT images prove only minor retinal changes caused by the implant. The electrode array of the implant was observed as beeing constantly well positioned within the eye. This fact is also indicated by the stability of threshold levels necessary for stimulation. These results verify the safety of the implant, its stable fixation and the good toleration of the implant by the eye for years.
Clinical Trial: :
www.clinicaltrials.gov NCT00427180
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • retinal degenerations: hereditary • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)