Anatomical basis of "senile" ectropion.

A study of 20 patients with bilateral ectropion was undertaken to determine the exact anatomical etiology of the horizontal eyelid laxity which leads to "senile" (involutional) ectropion. Two previous studies on normal people have shown a slight increase in the horizontal length of the lateral canthus with increased age. The results of the 20 patients with ectropion revealed that the lateral canthal tendon is significantly increased in horizontal length as compared with normal, age-matched controls. Therefore, surgery directed to the repair of the attenuated, horizontally lax, lateral canthus is more appropriate than full-thickness block or tarsal resection of the normal eyelid in the palpebral fissue. Additionally, since normal full-thickness eyelid tissue is not resected, the horizontal length of the palpebral fissue will not be shortened. This results in a more pleasing cosmetic appearance as well as an improved functional result.