Abstract
Abstract: :
Pupose: To evaluate juxtascleral drug delivery devices placed in the Rhesus macaque animal model, demonstrate surgical implantation, retrievability, device stability, and the effect on retinal and choroidal blood flow. Methods: Study A evaluated 2 preliminary devices in the left eye of 14 animals (2 sham surgeries). Devices were implanted between the sclera and the inferior oblique (IO) muscle using an anterior conjunctival peritomy followed by blunt dissection between the optic nerve and the IO insertion. Devices were localized relative to the fovea with ultrasonography. Slit lamp examination, indirect ophthalmoscopy, high-speed scanning laser ophthalmoscopy with video fluorescein and indocyanine green angiography were performed prior to implantation, immediately post-operative, then at week1,3, and 10. Study B evaluated either of 3 re-designed smaller devices in the right eye of 9 rhesus using modified surgical technique and similar examinations. Results: Study A: Devices were surgically placed in 1 to 35 minutes (mean = 9), and all were localized near the fovea. Intraoperative complications include 2 small extraocular hemorrhages. Postoperative complications include 2 conjunctival dehiscence and device exposures, 7 with retinal striae, 2 choroidal filling defects (one sham), 1 retinal pigment epithelial (RPE) disturbance, 1 with choroidal thickening, and 1 with possible cystoid macular edema. No animals had detectable retinal blood flow abnormalities or device migration. All devices were retrieved without difficulties (<1 to 6 minutes, mean = 1.5) Study B: Re-designed devices were placed in 10 to 60 minutes (mean = 26), and all were localized near the fovea. Intraoperative complications include 2 mild extraocular muscle hemorrhages that resolved. Postoperatively, there were no device exposure problems, RPE changes, choroidal thickening, definite choroidal blood flow defects, or cystoid macular edema. Postoperative complications included moderate device migration (9/9) and fine, transient retinal striae (5/9). Surgical retrieval were 2 to 8 minutes, mean = 3. Conclusion: Modification of the transscleral drug delivery device to accommodate Rhesus anatomy decreased the postoperative complications seen with the larger preliminary devices. Dissection of the intermuscular septum improved drug core localization near the fovea, but increased surgical time and decreased device stability.
Keywords: age-related macular degeneration • pharmacology • animal model