Distichiasis is defined as a second row of eyelashes arising from which location?

Distichiasis is defined as a second row of eyelashes arising from which location?

• A. From the meibomian gland opening
• B. From the eyelid margin
• C. From the eyebrow
• D. From the lacrimal duct

Answer: (A)

Distichiasis refers to a second row of eyelashes that originate specifically from the openings of the Meibomian glands along the posterior edge of the eyelid margin. The Meibomian glands sit in the tarsal plate with their orifices at the back of the lid margin, so when hair follicles form there, extra lashes grow in a second row and can irritate the eye. Lashes from the eyebrow or from the lacrimal duct are not the source of distichiasis, and simply saying “eyelid margin” is less precise than pinpointing the Meibomian gland openings.

Distichiasis refers to a second row of eyelashes that originate specifically from the openings of the Meibomian glands along the posterior edge of the eyelid margin. The Meibomian glands sit in the tarsal plate with their orifices at the back of the lid margin, so when hair follicles form there, extra lashes grow in a second row and can irritate the eye. Lashes from the eyebrow or from the lacrimal duct are not the source of distichiasis, and simply saying “eyelid margin” is less precise than pinpointing the Meibomian gland openings.