Distichiasis is a condition where eyelashes emerge from a structure in the eyelid (meibomian gland) which does not normally produce hairs. These "extra eyelashes" emerge so close to the eye that they can contact the ocular surfaces and can cause discomfort and corneal damage. Distichiasis is considered an inherited problem as it is much more common in certain breeds of dogs including Shih Tzus, Lhasa Apsos, Golden Retrievers, and Cocker Spaniels.
The severity of the problem and the need for treatment vary from patient to patient. Some patients may have only a few, soft distichia on a single eyelid while others may have full rows of abnormal hairs on all eyelids. Although some patients with distichia are asymptomatic, many animals require treatment in order to alleviate irritation caused by the hairs rubbing on the cornea of the eye. Signs that can be indicative of ocular irritation include redness of the eyes, squinting, ocular discharge/tearing, and/or rubbing at the eyes.
Sometimes distichia can cause corneal ulcers or erosions when the hairs touch the cornea of the eye. Corneal ulcers can be very painful and can lead to vision loss in severe cases.
Pulling out the abnormal hairs in the exam room may provide temporary relief, but these lashes almost always grow back. Topical ointments may be used to help lubricate the eyes, which can provide some relief from the abnormal hairs. Depending upon the patient, surgery might be recommended as the ideal approach.
There are several surgical options for distichiasis. The one that shows the highest success rate and is therefore usually the approach recommended at Northwest Animal Eye Specialists is cryosurgery. For low numbers of distichia, electroepilation might be used instead. Cryoepilation works by freezing the affected area of the eyelid to kill the hair follicle. Although electroepilation or cryosurgery should prevent the distichia from growing back in the treated areas, there are numerous places along the lids where new distichia could potentially emerge. Additionally, there are occasionally stubborn follicles that are resistant to cryosurgery, which can result in a recurrence at that site. For these reasons, up to 10% of dogs will require a second procedure in order to eliminate any new aberrant hairs. This is more of a concern in young and/or severely affected dogs.
The main side effects that may result from these surgeries are eyelid swelling, loss of eyelid pigmentation, and/or loss of hair in the affected areas. In most cases, these effects are only temporary.