Feline eye disease – Here’s a long and comprehensive list. The first thing to do is to define the phrase “disease” in the search term (another search term is “cat health eye” by the way). It is easy to acquire a misconception with regard to terminology. The word “disease” can be used in a very wide sense. Essentially it means an abnormal condition that exists in an organism (meaning in this instance, a cat) that affects in a negative manner the normal working of the body. The negative impact can mean the death of the organism.
|Cat eye photo by nicora – healthy eye|
Sometimes we limit the term “disease” to mean infectious diseases (or at least I do). An infectious disease is one in which the normal working of the body is affected negatively by the presence of a pathogenic microbial agent, which is a very small object that causes disease. A well known example would be a virus. An individual viral particle is a minute object (sub-microscopic) that consists of DNA or RNA (genetic material) coated by a protein shell and which has to “live” inside a cell of the host, where it reproduces. Its presence kills the cell. When this happens a lot the host organism (in this case the cat) suffers with symptoms of illness.
Cat’s eyes are a very important sense for the cat and they are adapted to stalking and hunting particularly at dawn and dusk (crepuscular activity). They are large. If our eyes were the same size as a cats in proportion to our body they would be 8 inches across (src: Cat Owner’s Home Veterinary Handbook by Drs Carlson and Giffin). They have two readily apparent differences to ours (a) a mirror like layer of cells behind the retina at the rear of eye, which reflects light back to enhance the image in dark conditions and (b) an extra eyelid that can be seen sometimes and which serves to protect the eye when walking through brush and tall grass, for example, and to keep the eye clean. Feline eye disease therefore has a major impact on their lives. A cat sees slightly differently to people – see a comparison.
Note: A number of these diseases and conditions are painful to very painful (scratched cornea for example) and therefore a cat owner should seek prompt veterinary care.
Returning to feline eye disease in the widest sense; here is a highly summarized list. It is is meant to provide pointers for non-qualified people, no more:
1. The eyes bulges from the eye socket (bulging eye) – several possible causes include (a) a blow to the eye fracturing the bones around the eye resulting in a build up of blood/fluid behind the eye forcing the eye forwards, (b) sinus infections spreading to the eye (c) a growth, malignant or not, behind the eyeball forcing it outwards and (d) “hard eye” – glaucoma (see below). But also see caption to image above.
Update: another example of feline glaucoma:
2.The eye sinks into the eye socket (sunken eye) – causes (a) dehydration and rapid weight loss (b) eye retractor muscle in spasm, which can be due to a tetanus infection or corneal injury (c) damage to nerve in the neck of the cat due to a neck injury for example (d) severe injury.
3. Jerky eye movements – indicates a problem with the inner ear.
|A much loved cross eyed cat called Tully – photo by johnnyalive|
4. Cross eye – Siamese cats commonly suffer from this feline eye disease and it is an inherited (genetic) condition. Other causes are (a) muscle paralysis (b) brain tumor (c) nerve injury. The classic Siamese cat squint does not affect bipolar eyesight. Inherited reason why Siamese are cross-eyed.
5. Inflammation of the eyelids – caused by (a) fighting leading to an infection, which in turn leads to scratching and more damage (b) mange mites (c) ringworm infection.
6. Foreign bodies – seeds or wheat (during harvesting) are one example. Causes discomfort and watering.
7. Sudden swelling – a feline eye disease caused by an allergic reaction from insect bites, allergens in food and/or drugs.
|Eye lost in car accident|
8. Eye lash irritation – Eyelashes although rare for cats can turn inwards causing irritation.
9. Rolled in eyelid – (a) can be inherited in Persian cats and (b) in any cat due to conjunctivitis or a lacerated eyelid. Also thought to be a disease affecting the Bengal cat. Called Entropion. Very uncomfortable. Affects people as well.
10. Rolled out lower eyelid exposing eye to irritants – the feline eye disease is caused by (a) birth defect (b) badly healed cut of the lower lid.
11. Cancer of the eyelid
12. Film over the eye – this is an opaque third eyelid becoming visible (it is called the nictitating membrane, “haw” or in latin: palpebra tertia). Caused by (a) ill health generally (b) injury (c) combined with bulging eye – see above (d) combined with sunken eye – see above (e) Key-Gaskell Syndrome (f) Horner’s Syndrome (g) Haw Syndrome. The haw is designed to protect the eye. Associated page: what can the third eyelid tell us?
13. Watery eye – tear stain overflow – tears running down the face – cause (a) eye is irritated and watering too much (b) feline viral respiratory infection (c) poor tear drainage due to blockage or over breeding (Ultra Persians and Ultra Himalayans suffer from this due to the flat face) (c) infection of the duct drainage system (d) injury (e) cancer. My cat suffers from this and his vet says it might be due a foreign body trapped in the nose or perhaps at he back of the mouth. We are not sure. It may be cancer of the nose.
14. Red eye (pink eye) – conjunctivitis – common feline eye disease – it is an inflammation of the membrane covering the back of the eyelids and the surface of the eyeball up to the edge of the cornea (front of the eye). 3 types: (a) Serous Conjunctivitis – mild condition – causes (i) early sign of feline viral respiratory disease (ii) allergens, irritants (b) Purulent Conjunctivitis – “purulent” means discharge from the eye contains pus – cause (a) secondary bacterial infection (b) virus if both eyes are affected (c) Clamydia – one eye first (d) Mycoplasma – one eye first (e) fungal infection – rare (iii) Follicular Conjunctivitis – mucous glands near the eye become rough which irritates the eye – cause (a) pollens (b) allergens (c) infections. See more.
15. Eye Worms – these are worms transmitted by flies that eat eye secretions. They are relatively large and can be physically removed by the veterinarian.
16. Cloudy eye – is what it says – loss of transparency. Can be localized or all over the eye – causes (a) keratitis – see below (b) glaucoma (c) cataracts. Requires urgent vet attention.
17. Corneal abrasion – loss of transparency – the cornea is the front, clear, part of the eye – caused by (a) injury resulting in a scratch (b) eye lash irritation if high up on cornea – 8 above (c) embedded foreign body – lower part of cornea. See Cat Eye Scratch.
18. Corneal Ulcers – loss of transparency – cause (a) injury to cornea (b) infection from virus, bacteria and/or fungus (c) diet. Urgent treatment is important is required to avoid this feline eye disease causing greater damage.
19. Keratitis – inflammation of the cornea – eye discharge, squinting, rubbing and protrusion of 3rd eyelid. The difference to Conjunctivitis is that eye discharge is not chronic and this is painful. This condition causes loss of transparency of the cornea. Two types (i) Ulcerative Keratitis – cause (a) injury causing abrasion or ulcer, which becomes secondarily infected (b) feline herpes virus and (ii) Chronic Degenerative Keratitis – unique to cats particularly Persians, Siamese and shorthair cats – inflamed tissue forms a black blob of opaque cornea -this feline eye disease has an unknown cause.
20. Cataracts – opacity of the lens of the eye. It might be a spot. Rare in cats cause (a) injury (b) infections (c) inherited (d) diabetic cats. Cats can usually get around alright unless severe. Read more if you’d like to…
21. Glaucoma – hard eye – caused by increase in fluid in the eye. Symptoms: tears, squinting, redness. If fluid pressure in the eye increases to more than 30-50 mmHg the eye becomes significantly larger. If left untreated the retina will be damaged and the lens become misaligned. Can occur quickly or slowly (weeks). Urgent action needed (vet).
22. Soft eye – inflammation of the inner pigmented area of the eye – this is a painful feline eye disease- squinting, watering – cause (a) infection (b) injury – penetrating (c) larvae of worms.
23. Retinal disease – the retina is the light sensitive cells at the back of the eye that capture the image and transmit it to the brain via the optic nerve. Eye loses ability to interpret the light received -causes (a) genetically linked PRA in Persians, Abyssinians and Bengals (b) inflammation from infection (c) hypertension (d) injury (e) dietary deficiency of Taurine affecting the center of the retina.
Feline eye disease – Primary Source: Cat Owner’s Home Veterinary Handbook by Drs Carlson and Giffin. This is a fine book, very comprehensive and I apologize if my tight summary is not up to scratch.
Feline eye disease photos: are either published under a creative commons license = Attribution-NonCommercial-NoDerivs License or are judged to be in the public domain. If that is incorrect please leave a comment.