Eye Disease in Cats

Cats are subject to a host of eye conditions that are similar to human eye problems. Cat eye health issues are one of the most common reasons for a visit to the vet. Eye conditions are caused by virus, bacteria, fungus, or trauma to the eye. The seriousness of the issue can range from something that will not limit your cat's activity greatly to a traumatic injury to the eye, warranting emergency care. 

Common symptoms of eye conditions and diseases include: 

• Squinting
• Excessive blinking
• Discharge from the eye
• Eye loses its transparency and becomes cloudy
• Eye sensitivity
• Tearing 
• Pawing at eyes
• Holding the eye closed
• Change in pupil size 
• Inflamed or crusty eyelids
• Hair loss on the eyelids 
• Reluctance to jumping on furniture
• Clumsiness

Just as there are hosts of eye issues in cats, there are a variety of possible causes including fungal, viral and bacterial infections, aging and genetic disease. The most frequent causes are: 

• Exposure to chemical irritants and environmental allergens
• A scratch to the eye
• Trauma to the eye
• Ingrown eyelashes
• Feline herpes virus (FHP)
• Feline immunodeficiency virus (FIV)
• Feline leukemia virus (FeLV)
• Feline infectious peritonitis virus (FIP) 
• Cryptococcus (a fungus found in soil)
• Uveitis, or inflammation of the front of the eye 
• Tumors
• Lens dislocation

Pink eye, or conjunctivitis, is very common in cats. The conjunctiva, the normally clear membrane covering the outer layer of the eye becomes inflamed, causing the eye to appear red and swollen. The conjunctiva plays a major part in the creation of tears, which protect the eye.

In older cats, just as in humans, cataracts often occur. A cataract in the eye clouds an area of the lens, which is normally clear. Proteins within the lens of the eye clump together and gradually cause the lens to break down. These clumps block light from reaching the retina. Over time, vision becomes greatly reduced and causes even partial blindness.

The cornea, which protects the front of the eye and also controls the amount of light entering the eye, has a sensitive surface and is subject to a variety of disorders. Unhealthy cells collecting in the sensitive outer layer and thereby diminishing the cornea's normal function is called corneal ulceration. 

Another very common condition in cats is glaucoma. Glaucoma is an increase of fluid pressure in the eye that occurs when the watery fluid the eye regularly produces just behind the lens (aqueous humor) does not drain properly. The accumulated fluid puts pressure on the optic nerve, which is the conduit between the eye and the brain. When pressure buildup is severe, the optic nerve becomes damaged and can lead to blindness.

A physical exam is not always enough to diagnose your cat's eye problem accurately. A complete medical history might be required as well as a thorough eye exam, taking scrapings from the eye, placing diagnostic coloured dye in the eye, and a tear test. 

During a routine physical examination, a veterinarian can often spot a simpler issue like conjunctivitis. To confirm the presence of glaucoma, the doctor uses a tonometer, releasing a puff of air against the eyeball to measure the pressure in the eye. The doctor might take blood tests to better determine the underlying cause of the eye issue, or recommend a visit to a veterinary ophthalmologist.

Though many eye issues in cats resolve naturally on their own without treatment, close monitoring is necessary. Luckily, most cases of eye disease can be treated on an outpatient basis. Because of the multiple possible causes, a variety of treatments might be administered in combination including surgery, oral or topical antibiotics, and eye drops. 

If your cat has cataracts, just as in humans, a cataract surgery is performed to remove the affected lens(es). Some conditions such as glaucoma are not curable, however, they are treatable. In many cases, eye drops relieve both the pain and clinical signs of glaucoma very effectively, and steroids reduce inflammation. Progressive vision loss is likely but will be slowed by a well-managed treatment plan. In the most severe cases of eye disease that are non-responsive to medication, surgery on the cat's eyelid flaps or removal of an eye might be necessary. 

At home, you will need to monitor the progress of your cat's response to treatment. If the issue is something contagious like conjunctivitis, it will be important to isolate the cat from other animals. During the recovery period, your cat may need to wear an Elizabethan collar and limit his activity. If the diagnosis is one of glaucoma, you will need to check the other eye for signs of developing glaucoma. Your veterinarian will give you advice on how to give your cat regular eye exams, how to keep a watch on changes in condition of your cat's eyes, and sound lifestyle advice for your cat.