Crossed eyes, also known as convergent strabismus, may appear at birth but can also develop later in life. Cats who are born with a convergent strabismus generally adjust to the condition on their own and enjoy a good quality of life. Cats who develop crossed eyes as adults may have a more serious underlying problem present.
Eye movement is controlled by small muscles that allow side to side and up and down motion. When one of these muscles is stretched out or too strong, or if the nerves that control the muscles are damaged, abnormal direction of the eye occurs. This is referred to as a “strabismus”. It can happen to one or both of the eyes. When the eye veers toward the nose it is called “esotropia”. When both eyes are misdirected at the nose, the cat will appear cross-eyed. This is known as a convergent strabismus.
What causes Convergent Strabismus?
The majority of convergent strabismus cases are due to genetics and are harmless to the cat. These issues can be seen from birth. Crossed eyes that develop later in life are generally an outward sign for an internal problem.
Known causes are as follows:
Vestibular system disease
Eye trauma from injury
Feline leukemia virus
A complete physical, neurological, and ophthalmologic examination will be performed. A neurological exam may include testing for reflexes, natural movement and ear issues. An ophthalmologic evaluation involves multiple eye response tests such as a Schirmer tear test, pupillary light reflex tests, tonometry and fluorescein staining of the cornea. Full blood work will be collected to run a Complete Blood Count and a biochemical profile. Urinalysis can help determine bodily functions and can reveal bacterial infections. X-rays of the skull may be needed to confirm the presence of tumors.
If the condition is not genetic, the underlying issue should be treated. Some causes of convergent strabismus are not serious, while others can be life-threatening.