Abstract: Objective To investigate the effect of iris pigment epithelium (IPE) pigment granules on the scarring process of filtration channels and the proliferation of Tenon's capsule fibroblasts after trabeculectomy in rabbits. Design Experimental study. Participants Eighteen healthy New Zealand rabbits. Method Rabbits underwent trabeculectomy in one eye. In the experimental group, 0.1ml (100 μg/ml) pigment granules extracted from hog IPE layer was placed under the scleral flap and retained permanently. In positive control group and the negative control group, 0.4 mg/ml mitomycin C and saline soaked in cotton chips were placed under the scleral flap for 3 minutes, respectively. The intraocular pressure (IOP) and filtering bleb morphology was recorded on postoperative day 1, 3, 7 and 30. The animals were sacrificed on postoperative day 30, pathological study was carried out on the filtration area of all rabbits. Main Outcome Measures IOP, filtering bleb morphology, and scarring degree of the filtration channel. Results The average IOP of experimental group, negative control group and positive control group before surgery was (24.78±1.40), (24.11±1.18), and (24.00±1.53) mmHg, respectively (F=0.241, P=0.789). On 30 days after trabeculectomy, the IOP of the experimental group, the positive control group and the negative control group were (20.28±1.87), (20.39±2.28), and (23.33±1.14) mmHg（F=22.500, P=0.000）. No statistical difference in mean IOP was discerned between the experimental group and the positive control group on postoperative day 30 (P=0.86), both of which was lower than that in negative control group (all P=0.000). The average survival time of the filtering blebs among the three groups was (28.17±1.72, 27.00±2.37, 10.67±1.97) days (F=138.592, P=0.000). HE and Masson staining showed that the experimental group and the positive control group had similar findings in pathological study, with relatively fewer collagen fibers and scar tissues. In the negative control group, a large amount of collagen fibers and scar tissue hyperplasia were discerned. Conclusion The short-term experimental study of small sample size shows that IPE pigment granules may inhibit the proliferation of Tenon's capsule fibroblasts, thereby delay the scarring process of the filtration channel after trabeculectomy. （Ophthalmol CHN, 2020,29: 32-37）

Key words: glaucoma, iris pigment epithelium, iris pigment granules, trabeculectomy