The Hairy Eyeball

The Hairy Eyeball

Did you know that the most common cause of eye ulceration or irritation is not from an external traumatic source, such as running into a bush or twig, but most commonly due to something right in the eye itself? One common cause is hairs in and around the eyes that grow inwards and can cause damage or irritation.

Normal hairs on the eyelid margin can irritate the cornea due to entropoin. Entropion is when the eyelid rolls inward and normal hairs on the eyelid irritate the cornea. This can be due an anatomical abnormality or spasm of the eyelid due to pain and irritation from another source which causes the eyelid to spasm and roll inward.

A second type of normal hair is called trichiasis. This is when normal hair that is growing toward the eye touches and causes irritation. The most common type is called medial canthal trichiasis. This is hair that grows from deep inside the corner of the eyelid particularly noted in brachycephalic breeds (short nosed) such as Shih Tzus, and Pekingnese.

Another type of hair, which is often difficult to see with the naked eye, is called distichia. These are tiny abnormal hairs that grow from glands (meibomian) on the lid margin.  When the animal blinks these hairs  rub on the cornea and can cause damage. There can be just one or a multitude of distichia hairs present.

A similar hair to the distichia is an ectopic cilia. They are typically singular or fewer in number as compared to distichia. They are more challenging to locate as they arise from the conjunctiva (pink tissue lining the eyelids) underneath the eyelid as opposed to the lid margin. Typically, eversion of the eyelid and magnification is required to visualize these hairs. They can cause significant irritation and damage due to their location.

Finally, the most bizarre type of hair noted in the eye, which is truly a “hairy eyeball”, is called a dermoid. A dermoid is displaced skin like tissue, often containing hair, which grows directly on the cornea (surface of the eye).

Typical hairs that are irritating the eyes can cause symptoms such as swelling, redness, cloudiness, squinting, rubbing, tearing or discharge. If any of these signs are noted, it is advisable to have your pet’s eyes examined. Possibly, the cause is due to one of these types of hairs. There are a variety of treatment options for each type and your veterinarian and a board certified ophthalmologist can help determine the best course of treatment for your pet.