Strabismus in Cats: Causes, Symptoms, & Treatment

You’ve probably seen cross-eyed cats in your life, and after marveling at their adorable expressions, wondered why they have crossed eyes. The condition that causes eyes to be continually crossed has a medical name: strabismus.

Strabismus usually doesn’t impact a cat’s quality of life and isn’t considered a problem in cats that are born that way, but if a cat suddenly develops strabismus later in life, it could indicate an underlying problem with the muscles that move the eye, or the nerves or the part of the brain that coordinates the movement of those eye muscles.

Read on to learn everything you need to know about strabismus in cats.

What Is Strabismus In Cats?

Strabismus is a common eye condition in cats that causes the eyes to be out of alignment with each other, resulting in a cross-eyed appearance. Small muscles control eye movement up and down, and side to side.

When an eye muscle is too short or too long, or if the nerves or part of the brain that controls the eye muscles are damaged, then the eyes move in abnormal directions, causing a cat to look cross-eyed.

Strabismus can affect the ability of a cat to focus properly, and may negatively impact that cat’s ability to judge depth properly. Strabismus does not cause blindness, and most cross-eyed cats born with strabismus adjust well to their condition and live completely normal, happy lives. Cats that develop strabismus suddenly as adults often have other underlying conditions that need to be addressed.

How Common Is Strabismus In Cats?

Strabismus is common in some breeds of cats, including Asian breeds like Siamese cats. In fact, many Siamese cats are cross-eyed because of congenital strabismus.

The most common type of congenital strabismus seen in Siamese cats and other Asian breeds is convergent strabismus, where the muscle on the inside corner of the eyes is too short, and pulls the eyeball toward the nose, giving the cross-eyed appearance. Divergent strabismus happens when the muscle on the outside of the eye is too short and pulls the eye(s) toward the side of the face.

What Causes Strabismus In Cats?

Strabismus can either be congenital, meaning the cat is born with it, or it can develop secondary to other conditions that affect the coordination of the eye muscles.

Most cats that have strabismus as kittens are born with the condition and inherited it from their parents. This is most common in Siamese cats, Himalayan cats, and Persians.

If a cat suddenly develops strabismus as an adult, then it is often a more serious condition that needs veterinary attention. Sudden onset of strabismus in an adult cat can signify a problem with the muscles that move the eyes, the nerves that supply those muscles, or the part of the brain that controls those muscles.

Viral, bacterial, or fungal infections can cause strabismus. Trauma, nerve damage, stroke, cancer, hydrocephalus (water on the brain), and even inner ear disease can cause strabismus. Strabismus that is due to a secondary condition is usually accompanied by additional signs of sickness in cats.

What Are The Signs Of Strabismus In Cats?

The most common sign of strabismus in cats is that the cat looks cross-eyed and is otherwise normal. Some cats may have difficulty judging distances when jumping, or they can’t see their food properly in a bowl, but they usually adjust their lives to their disability and do just fine.

The story is a little bit different for adult cats that suddenly develop strabismus. If you notice that one or both of your cat’s eyes are suddenly in an abnormal position, or if you notice the eyes moving in an uncoordinated fashion, or if your cat is acting sick in any way, seek veterinary attention as soon as possible.

Additional signs that might be associated with strabismus that indicate a more serious underlying condition include:

• Rapid eye movement side to side, up and down, or in circles (this is known as nystagmus)
• Pupils are different sizes, or don’t constrict when exposed to light
• Droopy eyelid
• Bulging eye
• Head tilt to one side
• Circling or falling to one side
• Seizures
• Weak and/or tired
• Not eating
• Vomiting
• Fever

If any of these signs are noticed, they are indications of a more serious condition. Seek veterinary care as soon as possible.

How Is Strabismus In Cats Diagnosed?

Your veterinarian will conduct a complete physical and ophthalmic exam. An ophthalmic exam consists of light reflex testing, eye pressure testing, and other eye tests, including Schirmer tear tests and eye staining. Your vet may also conduct a neurological examination, which consists of testing cranial nerve reflexes, leg reflexes, testing balance, watching your cat walk, and checking your cat’s mental state.

If your vet suspects that the strabismus is congenital and not impacting your cat’s health or wellness in any way, then that is all that will need to be done. If your vet suspects that the strabismus is due to another underlying condition, then additional tests will be ordered.

These can include bloodwork, testing for viral diseases, imaging studies, or referral to a veterinary ophthalmologist, neurologist, or internal medicine specialist.

Is Strabismus In Cats Treatable?

If a cat develops strabismus that is not due to genetics, then both the strabismus and the underlying condition can and should be treated.

Strabismus is often corrected with surgery.

Under general anesthesia, a surgeon can correct abnormalities in affected eye muscles to realign the eyes. Surgery can also be used to drain abscesses behind the eye causing by bite wounds. If strabismus is caused by a tumor, then surgery and often radiation therapy can be used to treat cancer. In some cases, removal of the whole eye may be necessary to keep it from spreading.

It may also be treated with medications.

Medications, such as antibiotics, may also be prescribed to help treat strabismus in cats with abscesses, meningitis, or inner ear infections that affect the vestibular system in the brain.

If your cat has had eye surgery to correct strabismus, be sure to follow all at-home instructions to give your cat the best chance at a good recovery and return to normal function. Keep a cone on your cat to prevent trauma to the surgical site, give all medications as prescribed, take your cat in for recommended rechecks and suture removal, and keep your cat indoors so you can monitor your cat’s recovery.

Physical therapy is also available after surgery or for cats that aren’t good candidates for surgery.

The goal of physical therapy is to strengthen eye muscles and coordinate eye movement and includes daily, fun eye exercises for your cat.

If your cat has strabismus and vertigo from a vestibular disease that cannot be treated, then you may need to prevent your cat from climbing up on high furniture to prevent injury from falling.

While strabismus in cats isn’t usually a major issue, it is still important to get your cross-eyed cats checked out by the vet, especially if things suddenly change. In addition, keeping your cat indoors and/or supervising your cat outdoors can help reduce strabismus related to trauma or infection.