Eyelash disorders result from abnormalities in eyelash growth. These disorders result in abnormal eyelashes irritating or damaging a dog’s cornea, leading to corneal ulcers, bacterial infections, blindness or loss of the eye. These disorders  include trichiasis, or in-grown eyelashes; distichiasis, or eyelash growing from an abnormal part of the eyelid; and ectopic cilia, or hair(s) that grow through the inside of the eyelid.

1. Distichiasis: The presence of so-called ‘extra eyelashes’ is referred to as distichiasis, where multiple abnormal hairs can be seen arising from the upper and/or lower eyelid margin
   

   A: Normal  B: Distichiasis  C: Ectopic Cilia D: Trichiasis

   Meibomian glands.  Canine distichiasis develops early in life, is very common and leads to varying degrees of irritation and damage to the cornea.  At VOR we treat these with cryosurgery if indicated, but not all cases need treatment.

2. Ectopic Cilia: Veterinarians usually erroneously refer to distichiae as ectopic cilia.  Ectopic cilia are single or discrete clumps of hairs that erupt through the inner conjunctival surface of the eyelid and are virtually invisible to the naked eye.  They are rare and usually in young adult dogs.  They tend to be intensely irritating due to the nature of their contact with the cornea, leading to marked blepharospasm and secondary ulceration.  All cases need treatment and at VOR where we excise them using an operating microscope.
3. Trichiasis: Finally, there is trichiasis, defined as normal hairs (usually ‘true’ eyelashes) growing in an abnormal direction.  The condition is moderately common and is seen in young Sharpeis and older dogs of some other breeds when upper lid lashes start curling over and contacting the cornea, leading to varying degrees of irritation and damage.  Cases requiring treatment at VOR are treated with a combination lid-lift and/or lash excision procedure.

Acknowledgement: Image From Slatter’s Fundamentals of Veterinary Ophthalmology