Corrosion cast demonstration of choroidal vasculature in normal Wistar Kyoto rat.

No previous attempt has been made so to demonstrate the details of the choroid vascularization in the rat. This paper describes the choroidal vascular pattern of the normal Wistar Kyoto rat using the corrosion cast method. 6-month-old normal Wistar Kyoto rats were used. Vascular casts prepared by our previously described technique were observed with a Hitachi S-2360N scanning electron microscope. Corrosion casts of the entire choroidal vasculature showed that the ophthalmic artery branched into two main ciliary arteries: the nasal and temporal arteries, which extend forward to form the iridociliary circle. Further the inferior ciliary artery arises from the temporal ciliary artery. In the posterior eye segment these arteries form four to seven branches supplying the adjacent choriocapillaris. There are different arrangements of choriocapillaris. The larger veins formed four vortex veins, one in each quadrant, draining blood from the anterior region of the choroid or iris. Venous blood from the central region, peripapillary choroid and sometimes optic nerve head is drained by smaller veins, which run more or less directly into the posterior ciliary veins. In conclusion corrosion casts and SEM can show the details of the choroidal vascular architecture. These three-dimensional (3-D) findings of choroidal vessels of the rat are very useful for the study of choroid vascular abnormalities in various pathological conditions.