Distichiasis is a condition in which there is growth of extra eyelashes (cilia) from the glands of the upper or lower eyelid. A hair follicle develops deep within the glands rather than on the skin surface of the eyelid. As the hair grows, it follows the duct of the gland and exits from the gland opening along the smooth surface of the eyelid margin. In many cases, these eyelashes, called distichia, rub on the cornea causing irritation and tearing, and occasionally corneal abrasions.
Distichiasis is considered to be an inherited condition in purebred dogs and can be seen in a wide variety of breeds. Commonly affected breeds include the American cocker spaniel, toy and miniature poodle, golden retriever, miniature long-haired dachshund, Shetland sheepdog, Chesapeake Bay retriever, English bulldog, Lhasa apso, and shih tzu. The disorder is seen rarely in the cat.
Clinical signs vary, depending on the number, size, position, and stiffness of eyelashes.
What to Watch For
Tearing from the eyes
Diagnosis
Generally, the diagnosis is made by visual inspection of the eye, identifying cilia (lashes) emerging from the meibomian gland openings on the edge of the eyelids, and possibly observing hair touching the cornea and/or conjunctiva.
A thorough eye examination is indicated to assess accompanying corneal changes and to rule out other causes of the above clinical signs.
A Schirmer tear test is performed to assess tear production in both eyes.
Fluorescein staining of the cornea is performed to detect any corneal abrasions or ulcers.
Treatment
Some asymptomatic dogs with short, fine distichia may require no treatment at all, and some may be managed conservatively, especially those with mild clinical signs. Observation is commonly recommended for American cocker spaniels because they are often very tolerant of their extra eyelashes.
Ophthalmic lubricant ointments may be used to protect the cornea and to coat the lashes in an oily film. Lubricants are most often chosen when mild tearing is the only clinical sign exhibited by the dog, if the lashes are few in number or short and fine in texture, or if the animal is not a good candidate for general anesthesia and surgery.
Surgical correction is undertaken to remove the lashes and kill the hair follicles if the dog is obviously bothered by the lashes, or if they are causing corneal changes.
There is no single ideal surgical procedure available, as the hair follicles can be very difficult to kill. If only one or two lashes are present, then that portion of the eyelid may be surgically removed. If multiple eyelashes are present, then cautery of the meibomian glands or freezing of the glands with cryotherapy may be chosen. Care must be taken with both procedures so that excessive scarring of the eyelids does not occur. Regrowth of hairs is a common problem and may necessitate repeated surgeries. Eruption of new hairs at new locations may also occur.
Home Care and Prevention
Administer all medication and return for follow-up as directed by your veterinarian. Dogs treated with medical therapy should be re-examined periodically, especially if they start to show new clinical signs. Following surgery post-operative rechecks are often required for 8 to 12 weeks to monitor for regrowth of the eyelashes.
There is no preventative care for distichiasis, although the breeding of two affected dogs to each other should be discouraged.
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