Background
Distichiasis is a rare disorder defined as the abnormal growth of lashes from the orifices of the meibomian glands on the posterior lamella of the tarsal plate. [1]
This picture demonstrates distichiasis of the lower lid. From Principles and Practice of Ophthalmology by Jakobiec.
The term distichiasis is derived from "distrix," describing the splitting of the ends of hairs, originating from the Greek words dis (two) and thrix (hair). [1]
Two types of distichiasis can be identified, acquired and congenital. In the acquired form, most cases involve the lower lids. Lashes can be fully formed or very fine, pigmented or nonpigmented, properly oriented or misdirected. The congenital form often is dominantly inherited with complete penetrance. It can be isolated or associated with ptosis, strabismus, congenital heart defect, or mandibulofacial dysostosis. This defect may be related to the failure of epithelial germ cells to differentiate completely to meibomian glands; instead they become pilosebaceous units. [1]
Pathophysiology
Distichiasis can affect the lower and upper lids (see following images). When these abnormal lashes come in contact with the cornea, they may cause severe irritation, epiphora, corneal abrasion, or even corneal ulcers.
This picture demonstrates distichiasis of the lower lid. From Principles and Practice of Ophthalmology by Jakobiec.
This picture demonstrates distichiasis of the upper lid. From Ophthalmic Plastic Surgery: Prevention and Management of Complications by Dortzbach.
Epidemiology
Frequency
United States
Distichiasis is a rare disorder.
Race
Distichiasis has been seen in all ethnic backgrounds.
Sex
This condition shows no sex discrimination.
Age
Distichiasis has been seen in all ages.
Prognosis
Fine lashes are usually well tolerated, but thicker eyelashes can threaten the integrity of the corneal epithelium.
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This picture demonstrates distichiasis of the lower lid. From Principles and Practice of Ophthalmology by Jakobiec.
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This picture demonstrates distichiasis of the upper lid. From Ophthalmic Plastic Surgery: Prevention and Management of Complications by Dortzbach.
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This picture demonstrates the cryotherapy of the lower lid with distichiasis. From Ophthalmic Plastic Surgery: Prevention and Management of Complications by Dortzbach.
