An experimental steroid responsive model of ocular inflammation in rabbits using an SLT frequency doubled Q switched Nd:YAG laser

摘要

Purpose: To develop a minimally invasive rabbit model of postoperative anterior chamber (AC) inflammation using a commercially available frequency doubled Nd:YAG laser [intended for selective laser trabeculoplasty (SLT)]. Methods: Escalating laser energy was applied to the iris of male Dutch-belted rabbits and the subsequent inflammatory response was observed to determine the laser dose required to generate self-limiting inflammation of at least 3 days' duration. In subsequent experiments, 10 eyes of 10 male Dutch-belted rabbits underwent baseline slit lamp examination, intraocular pressure (IOP), and AC flare meter readings. Starting 1 day before laser application, 5 animals received topical 20 μL dexamethasone 1% to 1 eye 4 times daily for 5 days. Five control animals were treated with saline. Masked assessments of flare, cells, and IOP were made daily for 7 days. Histopathologic changes were assessed in enucleated eyes. Results: Compared to controls, dexamethasone-treated rabbits had less postlaser AC flare on postoperative day (POD)2 (19±5 vs. 44±21photons/ms, P=0.03) and POD3 (16±9 vs. 33±11 photons/ms, P=0.03). In dexamethasone-treated rabbits, clinically graded flare (on POD1) and cells (on POD1 and 2) were lower than controls, but did not reach statistical significance. In the control group, IOP was significantly lower than the dexamethasone-treated group on POD2 (14.1±3.4 vs. 19.8±1.1 mmHg, P=0.03) and POD3 (14.2±2.2 vs. 19.0±2.2 mmHg, P=0.01). Histopathology showed pigment clumping and changes limited to anterior layers of the iris. Conclusions: Commercially available SLT laser can be used to create a minimally invasive, steroid-responsive animal model of anterior uveitis with the potential for use in the evaluation and comparison of drugs intended to treat AC inflammation.