Distichiasis

Distichiasis is an abnormality of the eyelid margin in which abnormal eyelash hairs (distichia) grow from the edge of the eyelid (usually from the openings of the Meibomian glands). These hairs, growing from an inappropriate location, point toward the surface of the eye and come into direct contact with the cornea, which can cause irritation, chronic inflammation, or even a corneal ulcer.

Typical symptoms:

Blinking/squinting
Increased tearing
Corneal clouding or ulceration

Diagnosis

The abnormal hairs are clearly visible with slit-lamp examination. The condition usually affects both eyes, and a genetic predisposition is suspected in certain breeds (e.g., Cocker Spaniel, Shih Tzu, Bulldogs, Shetland Sheepdog).

Treatment options

In mild cases, symptoms can be improved with appropriate ocular surface therapy. Eye ointments and gels form a physical barrier between the ocular surface and the hairs, reducing irritation. As a permanent solution, cryotherapy or laser removal is recommended, since these procedures destroy the hair follicles.

The appropriate treatment method depends on the number and location of the distichia, as well as the extent of ocular surface involvement.

Why is treatment important?

Continuous mechanical irritation leads to pain, causing the dog to begin squinting. Prolonged squinting can result in the eyelid turning inward (a condition called entropion), which further worsens the situation, as additional hairs come into contact with the ocular surface. This creates a vicious cycle.