Abstract
Abstract: :
Purpose: To compare the efficacy and safety of a new cross-shaped, non absorbable Polymethyl-Methacrylate (PMMA) implant with standard collagen implant in an animal model of deep sclerectomy. Methods: 10 rabbits underwent deep sclerectomy of both eyes and randomly received a cross-shaped PMMA implant in one eye and a collagen implant in the other. Weekly intraocular pressure (IOP) measures were performed during the 6 months follow-up. Ultrasound biometry (UBM) and fluorescein and indocyanin-green anterior segment angiography were recorded before and after surgery at 1,3 and 6 months. At the end of the follow-up period, outflow facility measurement and histology were performed. Results: The mean preoperative IOP was 13.4 (± 0.8) mmHg and 13.3 (± 0.8) mmHg for collagen and PMMA implants respectively. At 1 week, 1, 3 and 6 months after surgery, the IOP was 8.8 (± 0.8) mmHg, 9.5 (± 0.5) mmHg, 11.7 (± 1.1) mmHg, 12.0 (± 0.9) mmHg for collagen and 9.3 (± 1.5) mmHg, 9.6 (± 0.5) mmHg, 11.7 (± 1.2)mmHg, 12.1 (± 0.9) mmHg for PMMA. During the 6 months follow-up, UBM showed progressive and complete resorption of collagen implants and slight regression of the filtering bleb thickness. PMMA implants remained stable but regression of the filtering bleb thickness occurred faster. Proliferation of new drainage vessels was comparable for both devices on angiography images at 6 months. Histology showed 3.65 (± 0.92) new drainage vessels per viewing area for PMMA and 1.99 (± 0.57) for collagen. Mean outflow facility increased significatively to 0.241 (± 0.060) µl/min/mmHg for PMMA and 0.233 (± 0.078) µl/min/mmHg for collagen compared to the known ease of flow under physiological conditions. Conclusion: The cross-shaped PMMA implants were well tolerated and provided comparable results in efficacy and safety to the collagen implant.
Keywords: intraocular pressure • outflow: trabecular meshwork • sclera