In vivo assessment of subretinally implanted microphotodiode arrays in cats by optical coherence tomography and fluorescein angiography

• Published in: Graefe's archive for clinical and experimental ophthalmology Vol. 242; no. 9; pp. 792 - 799
• Main Authors: Völker, Michael, Shinoda, Kei, Sachs, Helmut, Gmeiner, Helmut, Schwarz, Thorsten, Kohler, Konrad, Inhoffen, Werner, Bartz-Schmidt, Karl Ulrich, Zrenner, Eberhart, Gekeler, Florian
• Format: Journal Article
• Language: English
• Published: Germany Springer Nature B.V 01.09.2004
• Subjects: Animals; Biocompatible Materials; Cats; Diagnostic Techniques, Ophthalmological; Electric Stimulation Therapy - instrumentation; Electrodes, Implanted; Fluorescein Angiography; Microelectrodes; Ophthalmology; Prosthesis Implantation; Retina - pathology; Retina - surgery; Semiconductors; Tomography, Optical Coherence
• ISSN: 0721-832X; 1435-702X
• DOI: 10.1007/s00417-004-0935-6

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. 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. 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. 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.