Trichiasis results from eyelashes that are misdirected against the ocular surface.

This is most often a consequence of eyelid inflammation and scarring, although it can be a presenting symptom of an eyelid margin malignancy as well.

Constant irritation can lead to eye pain, vision changes, corneal abrasions, or corneal ulcers. Although this condition is often idiopathic, certain conditions can contribute to this development, such as infection, inflammation, involutional changes, or trauma.

Before removing the malaligned contact between the eyelashes and the ocular surface, diagnosis of and understanding the underlying cause of trichiasis is essential.