The trabecular meshwork of 45 normal human eyes ranging in age from 19 to 81 years and of six glaucomatous human eyes (33–78 years) was studied for the presence of contractile cells. For this purpose, the chamber angle was immunocytochemically stained with antibodies against α-smooth muscle (sm) actin. Within the various ages, the presence of α-sm actin labelled cells showed differences. In younger eyes, α-sm actin filaments were seen in nearly all cells of the trabecular meshwork. With increasing age, fewer cells stained for α-sm actin and were mainly seen in the posterior part of the trabecular meshwork and in the scleral spur. The main filtering portion of the meshwork contained nearly no stained cells. No differences were found between glaucomatous eyes and normal eyes of the same age group.