In vivo assessment of subretinally implanted microphotodiode arrays in cats by optical coherence tomography and fluorescein angiography.
BACKGROUND
Following multiple promising investigations into restoration of vision in degenerative retinal disease by implantation of a sub- or epiretinal prosthesis, the step to clinical use in humans is impending. In this study we intended to establish optical coherence tomography (OCT) and fluorescein angiography (FA) first in research animals for noninvasive assessment of the condition of the posterior pole of eyes after intraocular implant surgery.


METHODS
Three adult cats that had undergone subretinal implant surgery were evaluated by OCT and FA between 1 and 470 days postoperatively. Eight adult cats served as control. In addition histology was performed.


RESULTS
In all three cats OCT demonstrated stable positioning of the implants in the subretinal space during the complete examination period. Transient retinal edema was found in the early postoperative period but decreased during follow-up. The retina over the implants was well attached at all times in cats 1 and 2; however, in cat 3 localized retinal detachment was demonstrated. FA showed intact retinal vasculature over the subretinal implant in high detail without interference from choroidal background fluorescence.


CONCLUSIONS
OCT and FA have been fruitfully applied to cats to assess the morphological and circulatory conditions of the neuroretina and of its interface with the subretinal implant. The techniques may therefore provide a tool for objective, noninvasive in vivo evaluation of eyes that have undergone subretinal implant surgery, both in research animals and in humans.
Völker
Michael
M
University Eye Hospital, Calwerstrasse 7/1, 72076 Tübingen, Germany.
Shinoda
Kei
K
Sachs
Helmut
H
Gmeiner
Helmut
H
Schwarz
Thorsten
T
Kohler
Konrad
K
Inhoffen
Werner
W
Bartz-Schmidt
Karl Ulrich
KU
Zrenner
Eberhart
E
Gekeler
Florian
F
D000818:Animals; D001672:Biocompatible Materials; D002415:Cats; D003941:Diagnostic Techniques, Ophthalmological; D004599:Electric Stimulation Therapy / Q000295:instrumentation*; D004567:Electrodes, Implanted; D005451:Fluorescein Angiography; D008839:Microelectrodes; D019919:Prosthesis Implantation; D012160:Retina / Q000473:pathology* / Q000601:surgery*; D012666:Semiconductors; D041623:Tomography, Optical Coherence
D001672:Biocompatible Materials