Abstract
Abstract: :
Purpose: To compare the efficacy and safety of hyaluronic acid coating in a new cross-shaped, non absorbable Polymethyl-Methacrylate (PMMA) implant in an animal model of deep sclerectomy. Methods: 8 rabbits underwent deep sclerectomy of both eyes and randomly received a cross-shaped PMMA implant in one eye and a cross-shaped PMMA implant coated with hyaluronic acid in the other. Weekly intraocular pressure (IOP) measures were performed during the follow-up of 4 months for 4 animals and 6 months for the other 4. Ultrasound biometry (UBM) were recorded before and after surgery at 1, 3 months, and before sacrifice. At the end of the follow-up period, outflow facility measurement and histology were performed. Results: The mean preoperative IOP was 14.1 ( ±0.8) mmHg and 13.9 (±1.0) mmHg for coated and simple PMMA implants respectively. A comparable IOP lowering effect was observed with, at week 1, 4, 12, 16 and 24 after surgery, a mean IOP of 9.5 (±1.1) mmHg, 10.8 (±1.6) mmHg, 11.9 (±1.3) mmHg, 11.4 (±1.3) mmHg, 12.5 (±1.3) mmHg for coated implant and 9.3 (±1.3) mmHg, 10.9 (±1.5) mmHg, 12.0 (±0.8) mmHg, 12.4 (±1.4) mmHg, 12.8 (±1.0) mmHg for simple PMMA implant. During the follow-up, both implants remained stable on UBM images with comparable regression of the filtering bleb thickness. Histology showed a similar number of new drainage vessels per viewing area at 4 month [3.9 (±0.7) for coated PMMA and 3.4 (±0.4) for simple PMMA] and 6 month [3.9 (±0.6) for coated PMMA and 3.3 (±0.9) for simple PMMA], suggesting that coating may slightly increased the proliferation of new drainage vessels during the first 3 months. Mean outflow facility increased to a similar rate for both implants at 4 month [0.24 (± 0.18) µl/min/mmHg for coated and 0.24 (± 0.08) µl/min/mmHg for simple PMMA] and 6 month [0.32 (± 0.10 µl/min/mmHg for coated and 0.28 (± 0.06) µl/min/mmHg for simple PMMA] compared to the known physiological outflow. Conclusion: The cross-shaped PMMA implants coated with hyaluronic acid provided comparable results in efficacy and safety to the simple PMMA implant.
Keywords: intraocular pressure • sclera • outflow: trabecular meshwork