Eyelash trichomegaly is increased length, curling, pigmentation or thickness of eyelashes. Various causes include congenital syndromes, acquired conditions and drugs. It can manifest at birth or present later in life.

It can form a part of spectrum of manifestations of some congenital syndromes. Although it tends to have a benign course, it can lead to psychological disturbances and can result in corneal abrasions and visual disturbances, if trichiasis occurs.