Eyelash disorders are very common in the dog and less common in other species. When abnormally positioned hairs contact the surface of the eve, they can cause pain and injury. Severe irritation can even lead to corneal ulceration and scarring. Signs of eyelash disorders include excessive tearing, squinting, Conjunctival redness, abnormal ocular discharge, pawing at the eve, and depression.

Distmichiasms is an abnormal condition in which extra eyelashes appear along the margin of the eyelid(s) where ordinarily they should not grow.  Distichiasis can occur in any breed, but there is a predisposition in the Cocker Spaniel, English Bulldog, Shih Tzu, Boston Terrier, Lhasa Apso, Golden Retriever, and Sheltic. This condition may be inherited.

In trichiasis, hairs growing from a normal location come in contact with the surface of the eye. Trichiasis occurs when normal hairs turn inward, when an eyelid margin is turned inward(e.g., lower medial entropion), or when hairs on a facial fold touch the eye. Trichiasis from facial folds and heavy brows occurs in breeds with very shortened noses (brachycephalics).

Ectopic cilia are abnormal hairs that are growing from the underside (conjunctival side) of the eyelid. These hairs usually cause severe pain and frequently lead to corneal ulceration. Ectopic cilia are more difficult to identify, requiring careful examination with magnification and a bright light source.

Various procedures are used to correct the different eyelash disorders. Nasal fold trichiasis requires surgical removal of the nasal fold. Lower medial entropion with secondary trichiasis is treated with surgical eversion (rolling outward) of the inner lower eyelid or by cryosurgery. In dogs with abnormally large eyelid openings, medial entropion with trichiasis may be corrected by surgical excision of the hairs with permanent partial inner eyelid closure.

Ectopic cilia are treated by cryosurgery and/or surgical excision. Cryosurgery uses extreme cold to destroy the roots of hairs, permanently removing at least 80% of treated hairs. Cryosurgery is the treatment of choice for distichia and some forms of trichiasis. It is more successful and causes less scarring than electrolysis.

Cryosurgical treatment of eyelash disorders requires general anaesthesia. Patients are then positioned under an operating microscope which provides magnification and a bright light source.

By Dr Victoria Pentlarge
Boarded Diplomate of both the college of Veterinary Ophthalmologists AND Internal Medicine