It consists of the ectopic growth of eyelashes in unusual areas of the lid margin, for example, they can emerge between or even from the orifices of the Meibomian glands. It can be congenital or acquired, causing the same problems of corneal irritation and trauma as trichiasis.

Treatment: necessary when corneal involvement is present, but must be treated with care, as treatment may not be as effective. Mild cases can be treated by topical lubrication with preservative-free artificial tears or by fitting a therapeutic contact lens.