The existence of smooth muscle adjacent to the Schlemm's canal of the normal albino rat eye.

The existence of smooth muscle adjacent to the rat aqueous outflow pathway was confirmed in this study. The smooth muscles ran parallel to the Schlemm's canal and reached the level of the posterior end of Schlemm's canal. The characteristics of these muscles were similar to smooth muscles in other organs. The existence of smooth muscle in this region depends on the fact that the rat eye lacks the scleral spur and the poorly developed meridional fibers of ciliary muscles come to lie close to the endothelial cells of Schlemm's canal. The innervation and function of these smooth muscles are unknown.