One day you look into your cat's usually clean face and see a rusty brown discharge underneath her eyes, almost as if she had been crying. If you own a white cat or one with a light-colored face, these so-called cat "eye boogers" may be especially apparent and unsightly. Generally, your cat's brown eye discharge can be wiped away and isn't serious.
Too many tears
The brown discharge you're observing is usually caused by an excess of tears. The brown staining means that the tears produced by your cat aren't draining properly, or he is making too many tears. The thin layer of tears on the surface of your cat's eyes lubricate them and prevent dryness. As in humans, their tears flow into tear ducts located at the corners of the eyes near the nose.
Epiphora in cats
The term for brownish eye discharge in cats is "epiphora." The discharge is a sign of a problem rather than a disease itself. When a cat's tear ducts become blocked, the tears track down her face. This is most common in cats with flat faces like Persians and Himalayans. In these breeds with squished-in faces, the tears fall right past the tear ducts and onto their face. These cats' long fur can also obstruct the tear ducts.
A number of eye conditions can cause excess tears. They may also cause an eye discharge that is usually clear or yellowish. Conjunctivitis is one of the most common causes of blocked eye drainage. Cat eye crust can impede tears running into tear ducts. Other conditions that might cause blocked tear ducts and excess tearing include eye injuries, eye infections, corneal ulcers and glaucoma. Chronic allergies can cause swelling adjacent to the tear duct and compress it.
Even eye lashes can cause excess tearing, especially in conditions where they grow abnormally from the inside edge of the eyelid and irritate the eye. A cat's eyes may not be formed properly due to anatomical abnormalities. Entropion, for example, is a genetic condition in which part of the eyelid is folded toward the eyeball. Some cats may have blocked ducts due to debris obstructing the openings or if for some reason the tear ducts failed to open as she was developing in the womb.
In addition to the brown discharge, you might notice your cat's face seems wet most of the time. There may be an odor, and the constant presence of tears may cause skin irritation or infection. Your vet will first do a thorough eye exam to determine if a disease or eye abnormality is causing the excess tears. If that's the case, that underlying cause will be treated. Your vet may do X-rays to look for tumors in the nose or sinuses. Magnetic resonance imaging or a computed tomography scan can also help detect abnormalities.
Treating the condition
If the tear ducts are blocked, your vet will likely anesthetize your cat so he can more safely examine the eyes. An instrument will be inserted into the ducts to dislodge and flush out whatever is blocking them. Sometimes allergies and even chronic infections narrow the already-small ducts. This flushing can help widen them so tears more easily drain.
Depending on the cause, the brown discharge may be a permanent condition. However, you can take some steps to lessen facial staining. Some pet owners have had success with adding parsley flakes to their cat's food. Ask your vet about various over-the-counter wipes that may help make the staining less noticeable.
Veterinarians used to prescribe low doses of antibiotics like doxycycline, tylosin, tetracycline, or metronidazole, which helped prevent excess tearing. However, due to antibiotic resistance, long term use of antibiotics is now discouraged.