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). See your veterinarian if you notice any swelling of the eyes.
Blepharitis refers to inflammation or infection of the eyelid, which is the fold of skin that covers the eyeball. Conjunctivitis refers to inflammation or infection of the conjunctiva, the loose connective tissue that covers the surface of the eyeball. Keratitis is inflammation or infection of the cornea, the transparent part of the eye that covers the front portion of the eye.
- 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 responsible 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). Surgery is the treatment of choice for primary entropion. Find and treat the underlying cause of secondary entropion.
- Allergies – Environmental factors such as pollens, smoke, fumes, dust are common allergens. The best way to treat allergies is to remove the allergen where possible. This will necessitate skin prick testing to determine the allergen.
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 bodies – Common foreign bodies include grass seed and grit, which may stick to the outer layer of the eyeball or embed into it. Scratches can cause localised swelling as well as a great deal of pain and discomfort.
- An eye or eyelid tumour – Surgery to remove the eyeball (enucleation). If the tumour is on the eyelid, surgical removal of the tumour and radiation therapy as a follow-up.
- Insect bite or sting -These resolve in time.
- Stye – An infection of the sebaceous gland in the eyelid. Treatment is cold compresses to draw out the infection and oral antibiotics.
The 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 the cat is displaying symptoms of an upper respiratory infection, feline herpes or calicivirus will be suspected.
- Eye swabs and bacterial culture and sensitivity -To determine the pathogen involved, this can help your veterinarian select the most effective antibiotic.
- Fluorescein eye stain – Orange drops are administered to show up any foreign bodies or corneal ulcers.
- Skin prick tests – To evaluate for common allergies.