Conjunctivitis is an
inflammation of the membrane covering the back of the eyelids and surface of
the eyeball up to the cornea. It is one of the most common eye problems in cats. Conjunctivitis in cats almost always has an
underlying infectious cause. The most common cause is the herpesvirus (FHV-1),
and the second most common is chlamydophila. Signs are a red eye, discharge,
and pawing at the eye to relieve itching. The conjunctival tissues may be red
and swollen. Untreated conjunctivitis may progress to vision-threatening
Conjunctivitis is not painful-although it is itchy. If the eye is red,
irritated, and painful to touch, consider the possibility of keratitis, uveitis, or glaucoma. Delay in treating
these conditions could result in loss of vision.
Cats like to scratch. They scratch during play. They scratch while stretching. They scratch to mark territory or as a threatening signal other cats. And because cats’ claws need regular sharpening, cats scratch on things to remove frayed, worn outer claws and expose new, sharper claws. Unfortunately, all this scratching can cause a lot of damage to furniture, drapes and carpeting!
This is a mild condition in which the membrane looks pink and somewhat
swollen. The discharge is clear and watery and is caused by physical irritants
such as wind, cold weather, dust, or various allergens. This condition must be
distinguished from a tearing problem.
Serous conjunctivitis may be the first sign of a feline viral respiratory
disease or a chlamydophila infection. Eye worms are a rare cause of conjunctivitis.
Treatment: Mild, irritating forms of conjunctivitis can be treated at home.
The eye should be cleansed with a dilute solution of boric acid for ophthalmic
use, artificial tears, or a sterile ophthalmic irrigating solution that can be
purchased over the counter and used as directed for people. You should see
definite improvement within 24 hours. If not, bring your cat to the
Purulent conjunctivitis begins as serous conjunctivitis that becomes
purulent. Thick secretions crust the eyelids. The eye discharge contains mucus or
pus. This suggests secondary bacterial infection.
When the discharge involves both eyes simultaneously, suspect a virus. This
could be herpesvirus or calicivirus. When it involves one eye at first and
progresses to the other eye several days later, suspect chlamydophila or
mycoplasma. These microorganisms can be detected under a microscope by your
veterinarian, in scrapings taken from the conjunctival membrane. Ulcers on the
cornea are diagnostic for herpesvirus conjunctivitis.