Trichiasis develops when hair arising from normal sites contacts the corneal or conjunctival surfaces. Distichiasis develops when cilia emerge from or near the meibomian gland orifices on the lid margin. These cilia may or may not contact the cornea. Ectopic cilia are single or multiple hairs that arise from the palpebral conjunctival surface several millimeters from the lid margin, most commonly near the middle of the superior lid.
Eyelash disorders are common in dogs and rare in cats.
Problems tend to occur most commonly in young dogs.
Any breed can be affected; however, some breeds are predisposed--breeds with prominent facial folds such as the pekingese, pug, and bulldog
frequently have facial fold trichiasis; most cocker spaniels have distichiasis to some degree; ectopic cilia are more common than average in the dachshund, lhasa apso, and shetland sheepdog, among other breeds.
Trichiasis From Facial Folds
Nasal corneal vascularization and pigmentation
Asymptomatic in most animals.
If stiff, stout distichia are contacting the cornea, blepharospasm, epiphora, corneal vascularization, pigmentation, and ulceration may develop.
Often cause superficial corneal ulcers with a linear appearance (corresponding to lid movement) on the superior cornea. These ulcers are resistant to healing until the underlying problem is diagnosed and corrected.
CAUSES AND RISK FACTORS
In most dogs, the disorder is related to facial conformation to breed predisposition, or it is idiopathic.
Other adnexal abnormalities (e.g., entropion), keratoconjunctivitis sicca, conjunctival foreign body, and infectious conjunctivitis should be ruled out. Diagnosis is made on the basis of direct observation of the abnormal cilia.
OTHER LABORATORY TESTS N/A
OTHER DIAGNOSTIC PROCEDURES N/A
Trichiasis can be managed conservatively in some animals. Keeping the periocular hair short may help; however, clipping the hair on facial folds may make it stiffer and more irritating. Surgical correction of adnexal abnormalities is indicated, such as entropion correction. Facial folds can be resected; however, a medial canthal closure is often a better procedure because it eliminates lagophthalmos and medial entropion as well as facial fold trichiasis.
Distichiasis is asymptomatic in most animals, and no treatment is indicated. When symptomatic, distichia can be treated surgically by cryotherapy, electrocautery or electroepilation, or resection from the conjunctival surface. Lid splitting techniques should be avoided because postoperative scarring can predispose to cicatricial entropion and impaired lid function.
Ectopic cilia should be treated surgically with an en-bloc resection of the cilia and associated meibomian gland. Cryotherapy can be used as the sole treatment method or as an adjunct after surgical resection.
DRUGS AND FLUIDS
Medical treatment is rarely indicated; however, lubricant ointments are sometimes valuable when used to soften cilia and lessen irritation before surgical correction.
Peri-operative, topically applied antibiotics are recommended in animals undergoing surgery in an effort to minimize conjunctival flora in the surgical sites.
CONTRAINDICATIONS/POSSIBLE INTERACTIONS N/A
Regrowth of distichia is common because destructive procedures such as cryotherapy and electroepilation have to be done conservatively to minimize lid damage.
Animals that develop ectopic cilia are at risk for developing ectopic cilia at other locations.
Owners should be advised to have their animal rechecked if clinical signs recur.
Gelatt KN. Veterinary ophthalmology. 2nd ed. Philadelphia: Lea & Febiger, 1991.
Author Erin S. Champagne
Consulting Editor Paul E. Miller