The essentials
- Dogs and humans have the same basic eye structure — Our canine companions have pupils, corneas, lenses, and retinas just like us, and they suffer from similar eye conditions, including cataracts.
- Cataracts are clouding of the eye’s lens — This is the part of the eye responsible for magnifying and focusing light onto the retina, which in turn allows a dog to see clearly.
- Not all cataracts are the same — While larger cataracts can significantly impair a dog’s vision, some cataracts are so small that they have no noticeable effect on eyesight.
In both dogs and humans, cataracts are the most common cause of cloudy eyes. While they vary in size and shape, cataracts commonly prevent light from properly passing through the eye in a way that results in impaired vision and, in advanced cases, partial or complete blindness. The good news is that most cases can be surgically corrected—but before we dive into treatment options, it’s helpful to understand what causes cataracts to form in the first place.
What are canine cataracts?
Cataracts are a clouding, or opacity, of the lens that is normally transparent in a healthy eye. Cataracts typically form when proteins in the lens break down and clump together, resulting in the characteristic cloudiness that restricts vision. They’re most common in older dogs, but cataracts can develop in dogs of any age, including puppies.
It’s important to note that not all cataracts will alter a dog’s vision. In fact, there’s so much variety among cataracts that they’re often classified differently based on the following factors.
Age of onset
The age at which a dog develops cataracts can offer insight into their underlying cause. In rare cases when cataracts are present at birth, a dog is said to have “congenital” cataracts. These cases are usually genetically inherited, but unlike other types of cataracts, they can improve on their own as a puppy matures. This occurs because their eye continues to grow, but the cataract may stay the same size. In these cases, the cataract is too small to negatively affect the dog’s vision when they’re full grown.
Cases developed between 6 months and 6 years of age are called “juvenile” cataracts. These can still be hereditary in nature, but can also occur from other causes, including inflammatory issues, progressive retinal atrophy, metabolic issues like diabetes, or physical injury. Juvenile cataracts have a notoriously rapid onset and can develop in as little as 24 to 72 hours.
🚨To minimize eye damage, seek immediate veterinary attention if you suspect your puppy may be developing juvenile cataracts.
Age-related or “senile” cataracts are the most common type of canine cataracts. Most develop slowly over a period of months or even years before significantly affecting a dog’s vision. Large breeds may start displaying signs of senile cataracts any time after age 6, while smaller breeds may not show signs until age 10. Like other types of cataracts, senile cataracts are usually attributed to genetics, but in some cases, may develop as the proteins and fibers that make up the lens break down with age.
Some older dogs experience lenticular sclerosis, where a gray-blue translucent haze develops behind their pupils. Though it appears similar to cataracts, lenticular sclerosis cannot cause blindness. Affected dogs may experience far-sightedness, or they may not be able to see fine details as clearly as before — but in general, their sense of vision should remain intact.
Anatomic location
The part of the lens being affected by cataracts similarly affects the way they’re classified. In some breeds like the Miniature Schnauzer, congenital cases occur in the central lens, which makes them easy to spot soon after their eyelids first open.
On the other hand, cataracts that develop rapidly due to conditions like diabetes can cause excess water to enter the transparent envelope around the lens known as the lens capsule, resulting in swelling and occasional ruptures along the middle and back (also known as the equatorial and posterior lens capsule).
It’s unlikely that a cataract will impair vision if it occupies less than 30% of the lens’s surface area (also known as an “immature” cataract). Overt impairment usually occurs at around 60% percent coverage (these cataracts are classified as “mature”), while blindness occurs when a cataract covers 100% of the lens.
Cause
Multiple factors can contribute to the development of canine cataracts. Most cases are genetically inherited, though both mixed and pure-bred dogs can be affected. Some breeds are prone to developing cataracts earlier in life, including:
Cataracts are becoming increasingly common among dogs with diabetes mellitus, with an estimated 85% of diabetic dogs developing cataracts regardless of their regulation level. In rare cases, changes in diet and insulin intake may be able to help slow the progression of these cataracts.
Less common causes of cataracts include old age, low calcium levels in the blood, and inflammation of the pigmented layer of the eye known as the uvea (uveitis). Cataract formation has also been linked to trauma or injury to the eye, exposure to UV light, radiation, and other toxic substances.
Some incipient cataracts have been linked to nutritional deficiencies that occur during development, especially deficiencies in amino acids like arginine and tryptophan, commonly found in a mother dog’s milk.
Opacity
Depending on how much a cataract is blocking the passage of light, it can be classified into one of five degrees of opacity, also known as maturation stages. These include:
- Incipient. These cataracts are so small, that they usually require magnification to be seen. Incipient cataracts take up no more than 15% of the lens and don’t impair a dog’s vision — which is why vets almost never recommend surgery for these.
- Immature. These cataracts cover between 15% and 99% of the lens, often occupying multiple layers and anatomical areas. Significant vision loss usually occurs between 60% and 75% coverage, though most immature cataracts produce relatively mild vision impairment. The retina is still partially visible in these cases, as characterized by an “eyeshine” medically called tapetal reflection.
- Mature. Cataracts in this category affect the entire lens, with zero tapetal reflection present during examination. Dogs with mature cataracts experience significant visual impairment, often in the form of near or total blindness. However, they may still be able to pick up changes in light if their retina is still in working order.
- Hypermature. In this stage, cataracts may start to dissolve on their own without treatment. Cataract resorption causes the lens to shrink and gives the capsule a wrinkled appearance, and typically results in inflammation deep in the eye (uveitis) that can result in glaucoma if left untreated.
- Morgagnian. This type of hypermature cataract is marked by a liquefaction of the outer part of the lens, also known as the lens cortex. This causes the lens nucleus to sink downward, increasing pressure on the lens capsule and the risk of complications from conditions like glaucoma. Morgagnian cataracts are characterized by profound vision loss that includes light and motion, but some cases are still surgically treatable.
Symptoms of cataracts in dogs
While vision impairment or loss is a common symptom among dogs with cataracts, it’s not usually apparent until the condition has significantly progressed. Earlier signs include redness in or around the eyeball due to protein leakage from the lens fibers; small, constricted pupils, and an increased sensitivity to light. Younger dogs may also squint or scratch their eyes in response to developing cataracts.
As the cataract spreads, you’ll start to notice whiteness on the pupils in one or both eyes. Around this time, your dog might exhibit signs of vision impairment. Common examples include bumping into furniture or missing thrown balls (especially on the impaired side).
🚨Take your dog to a vet as soon as you notice any changes in their eye color or clarity.
How canine cataracts are diagnosed
When you take your dog to the vet for suspected cataracts, the doctor will start by conducting a physical examination of the eye and surrounding structures. During this time, you’ll want to let them know when you first noticed symptoms and whether or not they have a history of other underlying conditions. Standard diagnostic procedures like blood and urine tests won’t detect cataracts, but they will detect diseases that cause them, such as diabetes.
From here, the vet will begin a series of specialized tests to confirm the presence of cataracts and gauge their progress. Many of these procedures will require them to dilate your dog’s eyes so they can get a better look at the structures inside.
Ophthalmic exam
In this test, the vet uses an instrument like an ophthalmoscope or head loupes to shine a light into a dog’s eye and check for opacities. Whether small or large, the presence of any abnormality is automatically diagnosed as a cataract.
Slit lamp biomicroscopy
This test is similar to an ophthalmic exam but instead uses a table-mounted microscope called a slit lamp to see even deeper into the eye. Slit lamp biomicroscopy allows for a three-dimensional of the inner eye, which allows the vet to measure the depth of abnormalities like cataracts.
Schirmer tear test
This test determines if the eye is producing enough tears to keep itself sufficiently moist. The vet places a small strip of filter paper inside a dog’s lower eyelid and tests it for moisture content upon removal. The Schirmer tear test isn’t used to diagnose cataracts themselves but offers a key indicator as to whether or not a dog can undergo cataract surgery.
Fluorescein stain
Also known as ocular stains, this test employs a combination of yellow or orange dye (fluorescein) and blue light to assess the integrity of the cornea. Ocular stains can detect scratches along the surface of the eye, as well as foreign bodies like cataracts.
Tonometry
In some cases, the vet may use this test to measure the pressure inside the eye (also known as intraocular pressure, or IOP) and see if inflammation from the cataract is causing it to fluctuate. To do this, the doctor numbs the eye with an eyedrop and then uses a thin, pen-like instrument to tap the surface. Tonometry measures IOP by measuring how much pressure is required to temporarily flatten part of the cornea.
In the event that your dog is a suitable candidate for cataract surgery, the vet may also conduct pre-operative tests, like an electroretinogram (ERG) and an ocular ultrasound, to assess the integrity of the retina. These tests require dogs to be put under anesthesia and may take a few hours to complete.
If your dog has experienced retinal damage, they will likely have some degree of vision impairment even after cataract removal. That’s why surgery isn’t typically recommended in these cases.
Most general practitioners don’t conduct these tests on-site, and will instead refer your dog to a board-certified veterinary ophthalmologist.
Treatment for cataracts in dogs
If your dog’s cataracts don’t cause vision impairment, they may not require treatment other than regular check-ups with the vet. If their cataracts are causing pain and inflammation, the vet may prescribe eye drops to mitigate symptoms. In these cases, owners must continue applying the drops for as long as the cataract is present.
When it comes to cataracts that cause vision impairment, surgery is the only treatment option currently available. The good news is that cataract removal has a very high success rate, with at least 85% to 90% of cases reporting partial or complete restoration of vision and zero health complications. Keep in mind that this figure only applies to dogs with healthy eye function excluding cataracts.
Since cataracts are known to progress at unpredictable rates, surgery should be performed as early as possible. The older a cataract is, the harder it is to remove. Eligible dogs will be administered pre-operative medication days or weeks before the procedure to minimize eye inflammation.
🚨To avoid adverse interactions with other drugs, vets recommend treating dogs for any underlying health problems before prepping them for cataract surgery.
The procedure itself is known as phacoemulsification and requires the ophthalmologist to use an ultrasonic probe to liquefy and remove the existing lens. After replacing lost fluids with a balanced salt solution, an artificial replacement lens (similar to a contact lens) is permanently fixed to the eye. Dogs typically require several months to completely recover from cataract surgery, but in many cases, lens replacement can restore almost all of their lost vision.
Research suggests that topical eye medications, including topical aldose reductase inhibitors (ARI eye drops), may have some efficacy in treating cataracts caused by diabetes.
The cost of treating canine cataracts
The high cost of cataract surgery is another critical factor when considering the procedure for your dog. Initial ophthalmology consultations cost between $200 and $300. Diagnostic tests like bloodwork and ultrasounds cost another $1,000 to $1,200, and surgery costs anywhere from $1,350 to $2,000 per eye. Today, the average cost of cataract surgery on both eyes is around $3,500.
This includes the surgery, anesthesia, hospitalization, and any subsequent medications your dog may require. In some cases, the cost of cataract surgery also covers an additional post-op checkup with the ophthalmologist.
👉Many pet insurance plans offer comprehensive coverage for vision-related issues, including cataracts. Check out our guide to pet insurance to find a plan that meets your dog’s health care needs.
With so many genetic and environmental factors at play, cataracts can be an unavoidable part of life for humans and our dogs. Watch for warning signs at home, and schedule regular check-ups with your vet to closely monitor the situation. Even if your dog does develop cataracts, the treatment is incredibly effective. You can rest easy knowing that it won’t be long before your buddy is back to their old selves, running around and fetching toys like there was never a problem.
Frequently asked questions
What do you do for a dog with cataracts?
Take them to the vet. Depending on the progression of the cataracts, your dog may not need any immediate treatment. However, if your dog’s cataracts are causing vision impairment, the doctor may recommend surgical removal to restore lost vision.
How long can a dog live with cataracts?
Cataracts don’t usually factor into a dog’s longevity, so your dog should live a relatively normal lifespan no matter how advanced their cataracts are. Secondary conditions caused by cataracts, like glaucoma, can produce significant pain and discomfort — but a dog can still have a high quality of life so long as medications are used to minimize their pain.
Are cataracts painful for dogs?
Cataracts themselves aren’t painful, but they can trigger painful secondary conditions, including inflammation of the eye and glaucoma.
How do you treat blindness in dogs due to cataracts?
In these cases, the only way to restore vision is to surgically remove the cataracts. In severe cases, an ophthalmologist will completely remove the eye’s lens and replace it with a permanent, artificial alternative similar to a contact lens. Partial or complete vision loss is reported in 85% to 90% of cataract surgeries, so long as the other parts of a dog’s eye still function normally.
Can cataracts in dogs be treated without surgery?
Usually, no. If your dog’s cataracts are so small that they aren’t causing vision impairment, no immediate treatment is required. If there’s no vision loss, but some degree of pain and inflammation, your vet will prescribe them eye drops to help manage symptoms. In any case where a cataract alters a dog’s vision, surgical removal is the only treatment option currently available.
Are there drops to break up a cataract?
No. While certain eye drops are marketed this way, there are currently no proven eye drops that aid with the dissolution of cataracts. Most cataracts are affixed to the lens, and can only be removed surgically.
