Abstract
Abstract: :
Purpose: To evaluate retinal alterations of the posterior pole following subretinal implantation of MPDAs by fluorescein angiography (FA) and optical coherence tomography (OCT). Methods: The retina above and around the implant, the implantation channel and the retinotomy site was examined by OCT in two anaesthesized cats before the implantation, at day 1, week 2 and week 6 after implantation. Modified FA was performed 6 weeks after implantation. Results: OCT revealed a flap at the site of incision at day 1, which completely disappeared at week 6. At week 2 and 6 no signs of retinal detachment at the site of the incision were seen. The subretinal channel between incision site and implant was closed without retinal edema after one week. The thickness of the retina overlying the implant was reduced as compared to normal cat retina. This is mainly due to the expectable deterioration of the photoreceptor layer after implantation as seen in histological sections. Minimal retinal edema was detected above the MPDA, which disappeared at week 2. No retinal edema or atrophy above the MPDA was detected (up to 6 weeks). The implant showed no dislocation. FA revealed hyperplasia of the retinal pigment epithelium along the area of the bleb and normal retinal perfusion around and above the implant. Conclusion: To our knowledge, OCT and FA were performed in cats after subretinal implantation of MPDAs for the first time. After implantation, MPDAs showed no signs of dislocation without further fixation. No retinal damage above and around the implant was found up to 6 weeks after implantation, except for the expected deterioration of the photoreceptor layer. The results show that OCT and FA are useful tools to monitor the posterior pole in cats after subretinal surgery. Apparently, the retina tolerates subretinal implants of various kinds (as MPDAs, drug pellets, etc.) very well.
Keywords: 432 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)