The histopathology of involutional ectropion.

Twenty eyelid specimens from patients with involutional ectropion, obtained by full-thickness horizontal shortening procedures, were examined histopathologically by light and electron microscopy and compared with six normal eyelids from exenteration specimens. Paralytic, cicatricial, and congenital ectropions were excluded from the study. The main histopathologic features included: (1) collagen degeneration and elastosis of the tarsal plate; (2) increased amounts of adipose tissue in the distal tarsus and capsulopalpebral fascia; (3) subacute inflammation and epidermidalization of the tarsal conjunctiva; (4) focal degeneration, fibrosis and elastosis of pretarsal orbicularis, and occasionally minimal change in the muscle of Riolan; and (5) arteriosclerosis of the marginal artery. The combination of these histopathologic changes characterize and may contribute to the development of ectropion of the eyelid associated with aging.