Experimental Study On Uveoscleral Pathway After Non-penetrating Trabecular Surgery In Rabbit Eyes

Objective To discuss the effects of non-penetrating trabecular surgery in rabbit eyeson the morphology of the uveoscleral pathway, and to explore the mechanisms of aqueous humor outflow at this procedure.Methods The right eyes were performed nonpenetrating trabeculectomy as study group, the regular trabeculectomy were operated in the left eyes as surgery control group, 12 rabbits(24 eyes)were used in both groups. Farther more 6 rabbits(12eyes) without operation served as normal control group. One week postoperatively, the anterior chambers were infused with microamounts of fluorescein isothiocyanate-bovine serum albumin(FITC-BSA) as the tracer while did so for normal control group. Three rabbits (two rabboits in experimental and surgery control groups, one rabbit in normal control group) each time were killed at 2,4,6,8,10 hours after infused ITC-BSA, their eyeballs were removed and frozen sections were performed. Degrees of fluorescent intensity of ciliary body, aqueous fluid pool ,suprachoroidal space, anterior and posterior sclera, and choroids were observed under fluorescence microscopy. Histological structures of these sites were also observed under light microscopy.Results Mean preoperative intraocular pressure(IOP) was similar in experimental and surgery control groups (2.22 0.35kPa in the experimental group and 2.02 0.32 kPa in the surgery control group, P>0.05),and there was nostatistically siginificant difference in IOP decrease at one week postoperatively(1.50 0.33kPa in the experimental group and 1.41 0.31kPa in the surgery control group, P>0.05 ). Compared with surgery and normal control groups, fluorescent intensities of alluveoscleral pathway sites were significantly stronger after NPTS. With light microscopy we found that ciliary intramuscular spaces weren't changed in every group but increased spaces of anterior scleral fibres and tiny detachment of ciliary body in experimental group.Conclusion Non-penetrating trabecular surgery can effectively lower the IOP as well as traditional trabeculectomy, increase uveoscleral outflow. Aqueous humor flows into the suprachoroidal space through the thin scleral bottom(aqueous humor pond) or ciliary body and out through anterior sclera predominantly, small amounts leave the eye through posterior sclera and choroid. So uveoscleral outflow is one of the main causes resulting in the decrease of the IOP in NPTS.