Eye swellings generally refer to the eyelids, the cornea (the clear, outer layer in front of the eye), and the conjunctiva, (a thin membranous layer surrounding the eye). Swelling can occur in one eye (unilateral) or both eyes (bilateral). Any swelling of the eyes should be checked over by a veterinarian as delaying treatment can potentially result in a loss of vision.
Blepharitis refers to inflammation or infection of the eyelid. Conjunctivitis refers to inflammation or infection of the conjunctiva. Keratitis is inflammation or infection of the cornea.
Eyelid abnormalities – Which are present at birth. Surgical correction of the abnormality may be necessary.
Viral infection such as the feline herpes virus, calicivirus, both of which cause upper respiratory infection including a runny nose and eyes, sneezing etc. The eyes can become inflamed and swollen. Treatment of these viruses is mostly supportive.
Bacterial infection usually occurs secondary to the viral infections listed above, the most common bacteria to cause conjunctivitis are Streptococci and Staphylococci. Antibacterial eye drops or oral tablets will be used to treat bacterial conjunctivitis.
Entropion is a disorder where the eyelid folds inwards, causing the eyelashes to rub against the eye, leading to inflammation. It may be primary (seen in short nosed breeds such as Persians and Exotics), or secondary (due to itching and rubbing the eyes). Primary entropion is treated with surgery, secondary involves finding and treating the underlying cause.
Allergies – Environmental factors such as pollens, smoke, fumes, dust being common allergens. Often the allergen isn’t known but if it is, then remove it from your cat’s environment, if possible.
Other symptoms associated with eye swelling can depend on the underlying cause but may include a red, meaty appearance to the eye, eye discharge which may be thick or watery, runny nose, fever, sneezing and pain. Allergies typically cause watery eyes and possibly itching.
Other causes of eye swelling:
Trauma or foreign body – Such as a grass seed stuck in the eye or a scratch can cause localised swelling and a great deal of discomfort.
Eye or eyelid tumour – Removal of the eyeball is necessary with eye tumours, eyelid tumours may be surgically removed. Radiation therapy may be given postoperatively.
Insect bite or sting. This should usually resolve by itself.
A styeis caused by an infection of the sebaceous gland in the eyelid and is treated by using a cold compress to draw out the infection and/or antibiotics.
Diagnosing the cause of eye swelling:
Your veterinarian will perform a physical examination of your cat and obtain a medical history from you. Accompanying symptoms can give your veterinarian an idea of the possible cause. For example, if your cat is displaying symptoms of an upper respiratory infection, then he will suspect herpes or calicivirus. He may want to run some diagnostic tests to determine the exact cause.
Eye swabs and bacterial culture to check for bacterial infections.
Fluorescein eye stain. A special orange dye is placed in the eye which will show up any foreign bodies.