If your cat has a weepy eye, it could be a minor irritant or a vision-threatening condition. It's normal for a cat to have a small bit of discharge after a night's sleep. But a constant discharge, or one containing any pus, requires a trip to the vet. Any eye problem is a potential veterinary emergency. Your vet will examine the eye and conduct tests to determine the reason for the discharge.
Upper Respiratory Infection
If your cat is also sneezing or exhibiting signs of a runny or blocked nose along with a weepy eye, he's probably suffering from an upper respiratory infection. Common disorders include three viral infections, herpesvirus, calicivirus and rhinotracheitis, and the bacterial Chlamydia felis. Your vet might take a sample of the eye or nasal discharge to determine the culprit. If Chlamydia felis is the cause, your vet can prescribe antibiotics to fight the infection, but these medications don't work against viruses. I there's a secondary infection related to a virus, she might prescribe antibiotics for that purpose. Your vet might prescribe topical antibiotics for the eye infection, but other treatment consists primarily of supportive care. You can have your cat vaccinated against these infectious agents, although the inoculations don't provide 100 percent protection.
Conjunctivitis in Cats
Commonly known as pinkeye, conjunctivitis in cats is sometimes a sign of a serious eye disease, such as uveitis or a corneal ulcer. At other times, it's just a mild infection of the conjunctiva lining the cat's eye and soon heals with topical antibiotics. In addition to the discharge, cats with conjunctivitis might have swollen, pinkish eye whites. Uveitis and corneal ulcers are quite painful, so your vet might prescribe medication for pain relief. A corneal ulcer might require surgery, while uveitis can require life-long topical steroid treatment.
Epiphora in Cats
Epiphora, the technical term for tear overflow, can result from blocked tear ducts, but that's not the only cause. Symptoms include constant wetness beneath the eyes, possibly with red staining. The discharge can smell and eventually cause a skin infection. Because of their facial structure, Persians and Persian-type cats often suffer from improper tear drainage. If your vet rules out other causes for the epiphora, such as conjunctivitis, she can flush out the tear ducts while your cat is under anesthesia. If the tear duct opening is too small, your vet can surgically widen it.
Colloquially known as dry eye, keratoconjunctivitis sicca occurs when the conjunctiva and cornea become too dry. Some of the symptoms are similar to conjunctivitis, but you might also see the "third eyelid" in the affected eye. Without treatment, keratoconjunctivitis sicca can cause blindness. Your vet will conduct the Schirmer tear test to determine eye wetness. Treatment consists of daily artificial tear applications to the eye, along with topical antibiotic and corticosteroid eye medication.