Distichiasis

From Dog
Distichiasis in both eyelids[1]

Distichiasis is an ocular defect characterized by excessive (trichiasis) or unusually placed (distichiasis) eyelashes[2].

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[3].

Symptoms include watering eye(s), recurring conjunctivitis, soreness and eyelid swelling. Concurrent cataracts, uveal cysts and coloboma may occur in predisposed breeds, e.g Cocker Spaniels[4].

Diagnosis requiring use of a magnifying glass or operating microscope examination of the eyelid.

A differential diagnosis would include other adnexal abnormalities (e.g., entropion), keratoconjunctivitis sicca, conjunctival foreign body, and infectious conjunctivitis should be ruled out.

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.

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. 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.

References

  1. Vetnext
  2. Raymond-Letron I et al (2012) Histopathologic features of canine distichiasis. Vet Ophthalmol 15(2):92-97
  3. Barnett, KC & Crispin, SM (2002) Feline Ophthalmology: An atlas & Text. WB Saunders Ltd, USA
  4. Engelhardt A et al (2007) Analysis of systematic and genetic effects on the prevalence of primary cataract, persistent pupillary membrane and distichiasis in the two color variants of English Cocker Spaniels in Germany. Berl Munch Tierarztl Wochenschr 120(11-12):490-498