Cataracts in Dogs

Miniature Schnauzer
Health Problems:
Cataracts in Dogs


Cataracts in dogs are one of those Miniature Schnauzer health problems that affect many other purebred breeds.

Indeed, it is one of the most common eye diseases in dogs, and suspected of being a genetic problem in about 97 breeds!

Are cataracts always hereditary?

How do you recognize if your dog has cataracts?

Can anything be done about them?

This Miniature Schnauzer information will give you the answers…

Which Dog Breeds Get Cataracts?

One study looked at the records of almost 40,000 dogs presented with cataracts at veterinary teaching hospitals in North America between 1964 and 2003.

Results of the study:

1. Though cataracts in dogs are most common in purebreds, around 1.61% of mixed breed dogs get them too.

2. Apart from the Miniature Schnauzer (4.98% affected), Purebreds with the highest risk of developing cataracts, were:

• American Cocker Spaniel (8.77% affected)

• Bichon Frise (11.45% affected)

• Boston Terrier (11.11% affected)

• Havanese (11.57% affected)

• Miniature Poodle (10.79% affected)

• Silky Terrier (10.29% affected)

• Smooth Fox Terrier (11.70% affected)

• Standard Poodle (7.00% affected)

• Toy Poodle (10.21% affected).


Breeds originally used to develop the Miniature Schnauzer from the Standard Schnauzer included the Bichon Frise and Poodle – likely sources of the cataract gene in our breed!


So, What are Cataracts in Dogs?

Cross section of the human eye
All light information processed by the eye has to first get through the lens.

A healthy lens is clear to allow light through.


In this cross section of an eye,
the lens is shown in yellow
A lens that becomes cloudy or milky is called a cataract. It’s like looking through a foggy window!

The extent to which a cataract interferes with the ability of the dog to see depends on how cloudy it is, as well as what parts of the lens are affected.

What Cataracts in Dogs are NOT Hereditary

Cataracts in Old Dogs

After about 6 to 8 years of age, the lens of most dogs normally become a bit pearly or hazy.

Sometimes called senile cataracts, this condition most often affects both eyes.

More correctly called nuclear sclerosis, this condition does not usually interfere significantly with sight.

Even though sharp edges and small shapes become harder to distinguish, they can follow general movements and actually compensate very well, relying more on smell, sounds and vibrations for their sensory input.

Cataracts Caused by Trauma

If the lens of the eye is damaged e.g. in an automobile accident, dog fight, by a thorn, or other object a cataract may develop. These types of cataracts usually occur in one eye only.

Cataracts Caused by Disease

Cataracts can be a side effect of other dog health problems including eye diseases such as uveitis, glaucoma, lens luxation and retinal degeneration, or systemic metabolic diseases – especially diabetes (it is seen in almost 40% of diabetic dogs) and Cushing’s disease.

Cataracts Caused by Infant Diet

Orphan puppies raised on cow’s milk formulas (i.e. rather than lactose free formulas) can develop cataracts due to the lodging of lactose proteins in the lens.

When Cataracts in Dogs ARE Hereditary

While the usual cause of cataracts is old age and/or diabetes, cataracts in young dogs (juvenile cataracts) are almost always hereditary.

So the age at which a dog develops cataracts is very important for determining if the cataracts are the result of a hereditary trait …or not.

Congenital Cataracts:

Cataracts present at birth are called congenital cataracts and usually occur in both eyes. Even these not necessarily inherited but can result from infections or toxins affecting the unborn puppies in the womb.

However, it does also occur as an inherited Miniature Schnauzer health problems.

Congenital cataracts generally do not advance to total blindness.

Juvenile Cataracts

In Miniature Schnauzers, Afghan Hounds and Standard Poodles, inherited cataracts can also develop in young dogs from about 6 months of age.

Again, cataracts at this age can also be caused by trauma, diabetes, infection, toxins, or infant diet.

How to Avoid Buying a Puppy with Inherited Cataracts

When considering obtaining a puppy of a breed known to carry genes for cataracts, ensure the parents have had their eyes tested by an ophthalmologist.

This reduces the risk but does not obliterate it altogether!

To add further confidence, avoid buying inbred puppies.

Just ask to see the pedigree (ancestry) of your puppy (or its parents) – if you see the same dog appear more than once or twice in the lines, the puppy is inbred and presents a higher than acceptable risk of developing any inherited disorder that may be present in the over-used ancestor’s genes.

For further information go to our

PRA page.

How to Slow Down Cataract Development…

Interestingly, recent studies show that nutrition plays in important role in preventing or delaying cataracts in older dogs.

Natural antioxidants, such as wheat sprout powder have been shown to reduce the development of cataracts significantly.

So obviously diet plays a role in cataract formation.

The North American veterinary teaching hospitals study mentioned above found that the prevalence of cataracts in dogs increased by 255% (i.e. more than tripled!!!) from 1964 to 2003.

Could this be linked to increased feeding of processed dog foods?

I think it is highly likely! Even the “elite” (i.e. very expensive) dog biscuits are still processed food! For life-long good health I recommend feeding your dog a natural diet.

Are Cataracts in Dogs Curable?

There is no way to restore clarity to a lens once it has gone cloudy. The only way to correct a cataract is to remove it surgically. This can only be done by a specialist veterinary ophthalmologist and is very expensive!!!

The usual process, called phacoemulsion, involves dissolving the lens with an ultrasonic probe and replacing it with an artificial lens

While most dogs regain good sight after surgery, 5 to 10% will show no improvement due to complications such as scarring, retinal detachment and glaucoma.

If left untreated…

…cataracts can cause inflammation inside the eye, which can only be controlled with anti-inflammatory eye drops for the rest of the dog’s life. To be successful, cataract removal surgery is best done before such inflammation develops.


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