The conjunctiva is the normally pink fleshy tissue under the eyelids. When it becomes irritated and inflamed, the condition is called conjunctivitis. The tissue will swell and turn bright red. The sclera (white part of the eyeball) is usually involved and will be blood-shot. Vessels dilate which are not normally apparent when the eye is healthy. Many factors can cause conjunctivitis including allergens (allergic conjunctivitis), chemicals like shampoos, and foreign bodies. Secondary bacterial infection of these delicate tissues is very common.
It is important to have any irritated eye examined by your veterinarian as soon as possible. Conjunctivitis can accompany very serious ailments of the eye such as corneal ulceration (an emergency), KCS (chronic lack of tear production), and glaucoma (increased fluid pressure inside the eye). Never reuse old eye drops or human prescription drops. Medications containing steroids can accelerate certain injuries to the eye leading to permanent damage or blindness. Your veterinarian will perform a complete eye exam which may include a Schirmer tear test, a fluorescein stain uptake test, and tonometry to measure intraocular pressure.
Inflammation of the conjunctiva causes dilation of the vessels that carry oxygen and antibodies to the tissues around the eye. This is what makes the fleshy tissue bright red. Occasionally, the inflammatory response may reduce the body’s ability to fight off bacteria in the eye which leads to secondary infection. Also, the tear ducts may not flow as well; the tears normally wash away contaminants and bacteria. A thick discharge of mucous will result which harbors the bacteria. This mucous should be gently removed with a warm wet gauze sponge, being careful to avoid touching the delicate cornea (the clear covering of the globe). Removing the mucous will help to prevent further infection as well as facilitate treatment of the conjunctivitis with topical ophthalmic medications.
After ruling out other serious problems with the eye, your veterinarian will prescribe an eye drop or ointment. An ointment may be a little more difficult to apply, but it has the benefit of remaining in contact with the tissues for a longer time than a drop. The medication will probably contain one or more antibiotic ingredients to give it a wide spectrum of activity against various bacteria found in the eyes. Culturing the eye is indicated in the case of resistant infections. The medication may also contain a steroid ingredient to help with inflammation. A steroid is indicated to treat allergic conjunctivitis.
Your veterinarian will also schedule one or more rechecks. If the eye looks worse in the meantime, you should alert the doctor immediately. It is important to follow up on any eye problem to avoid more serious problems that may lead to permanent injury or blindness.