Cataracts in Dogs: Signs, Causes, and Treatment

A dog cataract is an imperfection or a “clouding” of the lens of the eye.

The function of the lens is to allow passage of light and images directly to the retina where vision occurs.

What Are Cataracts in Dogs?

A dog's eye lens should be crystal clear, but diseases of the lens—like cataracts—can change its transparency or clarity.

Cataracts may initially be too small to interfere with vision, but often grow and can drastically impair vision.

It’s challenging to determine whether a small cataract will become larger and at what rate it will grow.

However, regardless of the size of a cataract, dogs will have diminished vision (like looking through a pane of frosted glass) and can even become blind from the cataracts.

Cataracts can cause secondary complications as well such as uveitis, glaucoma, and lens luxation, which are typically painful.

Often, cataracts in dogs can appear as a whitening effect or cloudiness to the dog’s eye and at certain angles or lights, may sparkle. You may witness a crystalline effect to the cornea.

Stages of Cataracts in Dogs

Dog cataracts develop in stages:

• The earliest stage—known as the incipient stage—affects less than 15% of the lens and don’t cause vision loss.

  • They are often pinpoint, and many dogs won’t notice these. Surgery to remove the cataract is rarely recommended at this stage.

• As the cataract grows and encompasses 15–99% of the lens, the cataract is at the immature stage. In this stage, vision is affected but still variable.

• The mature stage is when cataracts cover 100% of the lens, and near-blindness or blindness is noted. Dogs with mature cataracts can only see changes in light.

  • Dogs experiencing this stage should undergo surgery to remove them if all other systemic illnesses are under control.

• Over time, the lens begins to shrink, and the lens capsule appears wrinkled, leading to the hypermature stage. Lens-induced uveitis often occurs at this stage.

Signs of Cataracts in Dogs

The most obvious sign of cataracts in dogs is a cornea that appears cloudy, often milky-white.

At certain angles or in the right light, you might be able to see a crystalline deposit within the eye, but other signs are often unnoticeable, at least at first. 

You might notice the following:

• Your pup bumping into objects or hugging the walls when they walk

• Inflammation in or around your dog’s eye, typically described as a ‘red eye’

• Bulging of your dog’s eye globe

• Your dog squints, paws at their eye(s), or is rubbing their face/head on the floor or along furniture

• Your dog has increased thirst and/or urination, unexplained weight loss, typically associated with diabetic cataracts

Bring your dog to the veterinarian if you see any signs that the eyes have changed in color or clarity or if your dog is showing any signs of illness.

What Causes Cataracts in Dogs?

The most common cause of cataracts in dogs is hereditary/genetic disease.

Dog cataracts also occur commonly as a complication of diabetes mellitus. These cataracts develop quickly and can rupture the lens capsule leading to significant complications.

There are other causes that are much less common, such as:

• Old age, typically those 8 years and older

• Trauma, such as electric shock

• Inflammation of the eye’s uvea (uveitis)

• Low blood calcium levels (hypocalcemia or hypoparathyroidism)

• Nutritional deficiencies

• Exposure to UV light, radiation or toxic substances

Hereditary cataracts occur commonly in young dogs between 1 and 5 years old. Breeds most susceptible to hereditary cataracts are:

• American Staffordshire Terrier

• American Cocker Spaniel

• French Bulldog

• Labrador Retriever

• Miniature Poodle

• Miniature Schnauzer

• Boston Terrier

• Siberian Husky

• Yorkshire Terrier

• Welsh Springer Spaniel

Diagnosis of Cataracts in Dogs

To diagnose cataracts in dogs, your vet will ask about your pup’s medical history and previous health concerns, including when you first noticed the symptoms.

Then, your vet will perform a complete physical examination to check your dog’s eyes and structures around the eye.

Initial diagnostic testing (such as blood work and urinalysis) usually do not show any abnormalities unless there is co-existing disease, like diabetes or hypocalcemia.

During the initial eye exam, your vet will use several tests to make a diagnosis of cataracts. These preliminary test results will also establish a baseline for comparing your dog’s progress over time.

It may be necessary to dilate your dog’s eyes to get a better look at the outside edge of the cataract and the back of the eye.

Your vet may perform the following tests:

• Slit lamp biomicroscopy—A special light is shone in the dog’s eye, which allows for direct examination of the lens.

• Schirmer tear test—A small filter paper is placed inside the dog’s lower eyelid. When the paper is removed, it’s tested for moisture content to measure tear production.

• Fluorescein stain—Usually neon orange or yellow, ocular stains are used to evaluate the integrity of the surface of the eye, looking for defects to the cornea, such as scratches or the presence of any foreign materials.

• Tonometry—After numbing the surface of the eye with an eye drop, the vet uses a small “pen” to tap the surface of the eye to measure intraocular pressure.

If your vet is unable to do these tests—or the test results indicate an abnormality—you will be referred to a local, board-certified veterinary ophthalmologist.

If your dog is diagnosed with cataracts and it’s decided that surgery is needed, further testing will be done to ensure that the retina (the structure in the back of the eye that processes light information and sends it to the brain) is healthy.

Some cataracts occur secondary to or are associated with loss of retinal function or retinal detachment. Pre-operative tests to evaluate the retina include an electroretinogram (ERG) and an ocular ultrasound. 

These tests usually require your dog to be sedated and can take a few hours.

If retinal function is compromised, this will affect your dog’s ability to see well—even after cataract removal. In these cases, cataract surgery is not recommended.

Dog Cataract Treatment

There are no medical therapies currently available to reduce or “cure” cataracts in dogs. Currently, canine cataract surgery (called phacoemulsification) is the only option to treat dog cataracts.

To guarantee the best chance of restored vision after cataract surgery, the health of both the eyes and the dog are evaluated. This step is critical, as any underlying diseases such as a skin or a dental disease should be treated prior to cataract surgery.

Cataracts are a progressive disease, and if surgery is recommended, it should be done sooner rather than later.

Pre-operative medication must begin and continue for several days to a few weeks prior to surgery. This is to make sure any inflammation in the eyes associated with the cataracts is controlled.

The long-term success rates reported in dogs following uncomplicated cataract surgery range from 85–90%. Dogs diagnosed with diabetic cataracts can also achieve a similar success rate with surgery.

Cataracts that dissolve on their own without treatment is referred to as cataract dissolution, which can cause deep inflammation within the eye. The cataract completely blocks light from entering the eye through the lens and keeps your dog from seeing.

The condition is still treatable with surgery, but without treatment, the condition can develop into glaucoma.

Not all untreated cataracts develop into glaucoma, but dogs who have glaucoma are often not candidates for cataract removal surgery.

Medical and surgical treatments exist for glaucoma, but in general, it carries a poor prognosis for preserving long-term vision.

Dog Cataract Surgery Cost

Estimated costs for dog cataract exam, prep, and surgery are as follows:

• Initial exam with an ophthalmologist: $200–$300

• ERG, ultrasound and blood work: $1,000–$1,200

• Cataract surgery on both eyes: $2,700–$4,000, including pre-operative examination, surgery, anesthesia, operating room use, hospitalization, and post-operative medications

• The average cost is $3,500, which may include a post-operative checkup as well.

Remember that these costs are only estimates.

They may increase or decrease depending on the nature of the cataracts, the presence of systemic disease, and whether complications occur during or after surgery.

Recovery and Management of Cataracts in Dogs

After dog cataract surgery, pups are usually kept in the hospital overnight. At home, they must wear a recovery cone or inflatable cone to keep them from scratching at their eye.

You will be given eye drops to administer to your dog at least two to four times a day while at home. Your vet will specify how long your individual pup needs them.