Veterinary care includes diagnostic tests to determine the underlying cause of the red eye and guide subsequent treatment. Your veterinarian will do a complete medical history and physical examination to determine if the problem involves only the eye(s) or whether other changes are present in the animal.
A complete ophthalmic examination is required to determine the source of the redness and whether it involves inflammation of the external structures of the eye or the internal structures. Your veterinarian may refer your cat to a veterinary ophthalmologist for further evaluation using specialized instrumentation. The following tests may be performed during the eye examination: Schirmer tear test to measure tear production
Fluorescein staining of the cornea to check for ulcers
Tonometry to measure the pressure within the eye
Examination of the interior of the eye under magnification
Taking scrapings of inflamed tissues (such as conjunctiva and cornea) for cytologic studies to determine the type of inflammation present
Examination of scrapings of the eyelids to look for parasites
Submission of samples for culturing bacteria and other agents
Biopsy of masses around the eye
If uveitis is the suspected diagnosis or if your pet appears unwell, then further tests are indicated to identify diseases that are systemic (involve other systems). Common tests include a complete blood count, biochemistry profile, serum tests for tick borne diseases, systemic fungal infections, and toxoplasmosis, and possibly X-rays of the chest and abdomen.
Exact treatment requires establishment of a diagnosis.
An Elizabethan collar may be applied to protect the eye. Ocular inflammation may be irritating and your pet can cause more serious injuries to their eye if they scratch it with their paws, or rub it against carpet or furniture.
Infectious agents can be the cause of conjunctivitis, especially in cats, and can worsen ocular inflammation in all animals. Therefore, your veterinarian may prescribe a topical antibiotic or antiviral medication to treat or prevent infection.
Lubricant eye drops or ointments may be prescribed to reduce the dry feeling associated with some surface eye inflammation or to treat any deficiency in the watery tears (dry eye).
Numerous topical anti-inflammatory preparations can be used to diminish inflammation (redness) in the eye. It is important to reiterate that although they may make the eye appear better, these treatments are non-specific and do not replace treatment of the inciting cause. They can also exacerbate a pre-existing condition or lead to other complications. They should be instituted only upon direction of your veterinarian.
Topical corticosteroids are the most commonly used class of anti-inflammatory agents for non-infectious forms of conjunctivitis, keratitis and anterior uveitis.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are a second class of anti-inflammatory drugs, and may be used sometimes in the presence of certain infections.
Topical antihistamines may be tried to control inflammation associated with allergies, but they frequently contain other products (vessel constricting agents) that can be irritating to animals.
Occasionally systemic anti-inflammatory medications are used in conjunction with topical medications. These include antihistamines for the treatment of allergic conditions, oral NSAIDs to alleviate pain and inflammation inside the eye, and oral corticosteroids. The use of these products depends on the underlying cause of the red eye. It is important to note that systemic corticosteroids should not be used if infectious diseases such as feline herpesvirus or fungal infections are the source of the redness.
Swollen tissues may respond to warm, wet compresses.
Other treatments may be administered, depending upon the underlying cause.