A COMPARISON OF TRABECULECTOMY WITH TOPICALLY APPLIED TIMOLOL IN A RABBIT OCULAR HYPERTENSION MODEL

The difference in intraocular pressure (IOP) dynamics between trabecul ectomy and topical instillation of timolol was compared in a rabbit oc ular hypertension model. Twenty New Zealand white rabbits trabeculecto mized with subconjunctival retention of 0.3 mL C3F8 gas in the right e yes were used as animal models. One week and three weeks after the ope ration, the left eyes of the rabbits were given three drops of 0.5% ti molol, and IOP dynamics were compared between the two fellow eyes afte r intravenous infusion of 0.9% NaCl sterile solution. There were four parameters available in comparing IOP dynamics: Time Needed to Reach P eak IOP (TNRPI); Ascending Slope (AS); Peak IOP (PI); and Time Needed to Return to the Original IOP (TNROI). By this method, it was noted th at, at the 7(th) day after the operation, the eyes trabeculectomized w ith subconjunctival retention of C3F8 gas had lower IOPs than the eyes that received topical instillation of timolol (baseline IOP: 14.7+/-4 .2 vs. 19.5+/-2.5, p<0.001, PI: 16.4+/-5.2 vs. 26.2+/-9.3, p<0.001). I n addition, at the 21(st) postoperative day, after intravenous infusio n of 0.9% NaCl solution, the operated eyes showed less IOP spiking tha n the eyes that received topical instillation of timolol (TNRPI: 5.7+/ -2.1 vs. 3.9+/-2.3, p=0.014; AS: 0.8+/-0.5 vs. 2.7+/-2.6, p=0.003; PI: 21.2+/-7.8 vs. 27.9+/-8.6, p=0.014; and TNROI: 8.4+/-6.5 vs.12.6+/-7. 3, p=0.06). These results suggested that trabeculectomy, rather than t opical timolol, yielded better protection against IOP spiking in a tra nsient rabbit ocular hypertension model.