Cataracts in Cats: What You Need to Know
In humans, cataracts are the world’s leading cause of blindness. Cataracts in cats are rare, but the disease is still serious; if left untreated, it may lead to blindness. Thankfully, many cases of feline cataracts can be successfully treated.
What Is a Cataract?
Cataracts affect the lens of the eye. The lens helps to focus vision as light passes through the eye, allowing your cat to see. If this small structure becomes cloudy due to a cataract, it can no longer focus light resulting in blurry vision. The lens is made of mostly proteins and water. Clouding of the lens occurs due to changes in the proteins and lens fibres.
Cataracts in cats are less common than they are in humans and dogs. Furthermore, while humans and dogs can develop cataracts due to diabetes, cats with diabetes typically don’t get cataracts. They are also most common among older cats, and Burmese and Himalayan cats are genetically predisposed to the condition. However, cats of all ages and breeds can be affected.
Causes of Cataracts in Cats
Cataracts in cats can develop due to:
- Poor nutrition in early life
- Metabolic disorders
- Inflammation (as with cat cancer, glaucoma, trauma, autoimmune diseases or infection)
- Lens dislocation (typically after trauma or inflammation)
- Cats may also develop cataracts that are related to other diseases such as diabetes or hypertension
Cataracts may develop as a result of uveitis, a type of eye inflammation that can occur as a result of infectious diseases like feline immunodeficiency virus, feline leukemia virus, feline infectious peritonitis and toxoplasmosis. However, it is not always possible to identify the cause of cataracts.
Signs & Symptoms of Cataracts in Cats
Cats are very good at hiding discomfort and vision changes, so it’s crucial to look for potential signs of cataracts, such as:
- Hazy or cloudy appearance of one or both eyes
- Behavioural changes (hiding, reduced activity, bumping into familiar objects, difficulty finding their food bowl and/or litter box)
- Tentative or cautious behaviour in unfamiliar places or around stairs
While cataracts aren’t considered painful, some conditions that cause them can be. Because of this, a cat with cataracts might also squint or have discharge, redness and swelling around the eye.
Diagnosis of Feline Cataracts
To diagnose cataracts, your veterinarian may perform a variety of tests, including an eye examination and pressure tests. While general practitioners can diagnose most cataracts, they may refer you to a specialist such as a veterinary ophthalmologist, who can conduct more sophisticated tests.
These tests may include:
- Advanced eye imaging (including ultrasound)
- Eye pressure testing
- Blood tests for metabolic diseases and infections
If your vet either suspects or diagnoses cataracts in your cat, he or she may recommend that you see a Veterinary Ophthalmologist for further testing and treatment.
Types of Feline Cataracts
According to the Animal Eye Clinic, cataracts are classified according to severity and percentage of the lens affected. These classifications are:
- Incipient cataracts: Affect less than 15% of the lens
- Immature cataracts: Affect 15% to 100% of the lens; light can still pass through
- Mature cataracts: Affect the entire lens; light passage is impeded
Diagnosing the stage of feline cataracts is essential to selecting the best treatment option.
Treating Feline Cataracts
Identifying and addressing the underlying cause of cataracts is the primary approach to treatment. Once this is determined, definitive measures to delay or prevent cataract-related blindness can be considered.
Some common approaches include:
- Drugs: Steroids and nonsteroidal anti-inflammatory drugs can reduce eye inflammation.
- Surgery to remove the eye (enucleation):Depending on the underlying cause, removal of the eye may be advised, especially if the underlying cause of the cataract causes swelling and pain.
- Surgery to remove the cataract: Another common treatment is replacing the lens of the eye through cataract surgery, performed by a veterinary ophthalmologist.
Cat Cataract Surgery
Removing and replacing the lens with a prosthetic lens is strongly recommended for cats who qualify. If your cat receives cataract surgery, there are important steps you can take to help your cat recover.
For several months after surgery, you will probably need to apply topical eye medicine. Your cat should be kept in a confined space for at least three weeks, as complications like swelling and bleeding may occur. A pet cone should be used.
The Role of Nutrition in Feline Cataracts
Feline cataracts can occur in kittens as a result of inadequate nutrition. A study of hand-reared tigers in Open Veterinary Journal seems to support this. Adequate intake of amino acids (the building blocks of protein) are important for eye development in tigers. Presumably, the same is true when it comes to reducing the risk of cataracts in domestic cats.
Furthermore, studies in humans, for example the one in Nutrition Reviews, suggest that the risk of cataracts might be reduced with appropriate nutrition, especially intake of antioxidant vitamins, like vitamin C, as well as lutein, B vitamins and omega-3 fatty acids. A properly balanced pet food for your cat’s life stage can often provide the essential nutrients to support your cat’s eye health.