Expert: Jessica - 5/12/2010

Question
My Mum has a 10 year old desexed female Burmese cat. She is in good health generally but just recently (I month) has developed a severe squint to both eyes, both eyes turn inwards towards her nose, giving her a very cross eyed look.She has no discharge or redness or swelling to either eye and doesn't seem to be bothered by this, her appetite is still good and apart from being a little reluctant to jump up on surfaces ( because her eyesight is impaired?) seems to be her normal self. She is an indoor/outdoor cat and has had fight injury's in the past. What could cause this sudden squint?

Answer
Hi Kerry.  A squint, medically known as strabismus, can be common in Oriental breeds such as the Siamese and Burmese, but this has largely been bred out, especially of the Burmese.  Most of the affected cats are born with it, but some develop it later, although typically at a much younger age than your Mum's cat.  So chances are that this is related to a medical condition.

Your Mum's cat is likely suffering from a neurological condition.  Causes can vary.  Cancer involving the nervous system (or the eyes themselves) is a concern with these cats, and infectious diseases such as toxoplasmosis are another.  Some serious diseases that can cause neurological problems are carried by fleas and ticks.  While cancer is largely incurable, toxoplasmosis and many flea and tick borne illnesses are curable with antibiotics.  Sometimes there is damage done that cannot be reversed, although most symptoms resolve completely.  

Another condition that can cause these symptoms is vestibular disease.  This is a mostly unexplained condition that usually has no cause.  Sometimes it's caused by a severe ear infection or an ear polyp or tumor, but most times, there is no reason found for it.  The problem seems to originate in the middle or inner ear in most cases, but occasionally, the brain stem is the area where the problem lies.  When a cause is found, treating that problem can resolve the vestibular disease.  When the vestibular disease is “idiopathic”, meaning there is no underlying cause, the bout must be waited out.  The majority of cats recover from the episode without treatment in a couple of weeks.  However, some cats become nauseated because the condition is dizzying, and anti-nausea medications are usually prescribed.  Cats must also be closely watched to ensure they don’t suffer falls and are able to eat on their own, because some cats who are severely affected become unable to walk to or stand at their food bowls.  Vestibular disease may be an interesting consideration since your cat is unwilling to jump on surfaces any longer.

Viral illness such as the feline leukemia and feline AIDS viruses can be responsible for neurological signs such as these.  These are a real concern if the cat goes outdoors, but not if the cat stays inside and doesn’t have contact with any strange cats.  There is a simple blood test for both diseases.  Another disease called feline infectious peritonitis also causes neurological symptoms, but it’s quite uncommon in older cats.

One other problem that could be responsible for a squint is glaucoma.  Often, you would notice enlarged eyes with this condition.  Glaucoma can be caused by high blood pressure, which may be secondary to hyperthyroidism, an extremely common condition in cats over 8 years of age.  Diabetes is also a risk factor for glaucoma, and this is common in cats 10 years and older.  Some vets have the ability to test for increased pressure in the eye, indicating glaucoma, although you may need to be referred to a specialist to determine if glaucoma is a problem.

Certainly, a vet visit is in order to determine whether the sudden development of this kitty’s strabismus is something to be very concerned about.

Best of luck!

Jessica