PurposeTo show the distribution of an anticoagulant factor, thrombomodulin, in a rabbit eye.MethodsImmunohistochemical staining using polyclonal anti-rabbit thrombomodulin antibody was performed with the excised eyes of pigmented adult rabbits. Streptavidin-biotin method was used to obtain intense staining.ResultsThe endothelium of the chorioretinal vessels showed positive linear staining. The ciliary non-pigmented epithelium showed granular staining, while the pigmented epithelium stained negatively. The positive staining was also detected in the trabecular plexus endothelium. The vascular endothelium of the ciliary body stained weakly.ConclusionsIt is suggested that thrombomodulin in the vessel walls and the aqueous drainage apparatus works to maintain normal blood fluidity and aqueous outflow. The role of non-vascular thrombomodulin in the ciliary non-pigmented epithelium is unclear. Curr. Eye Res. 15: 938–942, 1996.