Hereditary Cataracts in Dogs: Which Breeds Are Affected and How to Test

Hereditary cataracts (HC) are one of the most common inherited eye conditions in dogs, distinct from age-related cataracts. They are caused by genetic mutations that can be identified through DNA testing. For breeders, understanding hereditary cataracts is essential for producing puppies that maintain their vision throughout their lives.

What Are Hereditary Cataracts?

A cataract is an opacity (cloudiness) in the lens of the eye. Hereditary cataracts appear earlier in life than age-related cataracts — some appear in puppies as young as 6 months, while others develop in young adults. Progressive hereditary cataracts can lead to partial or complete blindness.

Hereditary cataracts are distinct from nuclear sclerosis (a normal aging change in dogs over 7 that makes the lens look cloudy but doesn't affect vision) and from posterior polar cataracts (a non-progressive form common in several breeds).

Breeds at Highest Risk

The following breeds have documented hereditary cataract genes and should be tested:

DNA test available:

• Australian Shepherd (HSF4 mutation)
• French Bulldog (specific mutation)
• Boston Terrier
• Staffordshire Bull Terrier
• Siberian Husky (multiple forms, some DNA, some CAER only)
• American Staffordshire Terrier
• Miniature Schnauzer
• Old English Sheepdog

CAER exam essential (DNA not yet fully available for all forms):

• Labrador Retriever
• Golden Retriever
• Poodle (Standard, Miniature, Toy)
• Cocker Spaniel
• Bichon Frise

DNA Testing for Hereditary Cataracts

For breeds with an identified DNA mutation, the test results in:

• Clear (N/N): No copies of the mutation — will not develop the tested form of HC
• Carrier (N/HC): One copy — will not develop HC themselves but can pass the gene to offspring
• Affected (HC/HC): Two copies — will likely develop cataracts

In a responsible breeding program, at least one parent should be Clear to prevent producing affected puppies. Two carrier × carrier pairings will produce 25% affected offspring.

The Role of CAER Eye Exams

DNA tests only identify known mutations. Some forms of hereditary cataracts have not yet been traced to a specific gene mutation, making DNA testing insufficient on its own.

CAER (Companion Animal Eye Registry) exams are performed by board-certified veterinary ophthalmologists and evaluate the entire eye for all known inherited eye conditions. CAER certification lasts 12 months and should be repeated annually for breeding dogs.

For breeds where CAER is the primary screening tool (Labradors, Goldens, Poodles), annual CAER exams by a boarded ophthalmologist are the gold standard.

What to Look for in a Stud Dog

For any stud dog in an at-risk breed:

1. Request the DNA test results if a mutation is known for the breed
2. Request the current CAER certificate (dated within 12 months)
3. Check the CAER database at ofa.org under "Eye Registry"

A stud who is DNA Clear for the breed-specific mutation AND has a current Normal CAER exam is the ideal combination.

Implications for Breeding Decisions

If your dam is a carrier (N/HC) for hereditary cataracts, breeding to a Carrier stud gives you a 25% chance of producing affected puppies. Breeding to a Clear stud means no affected puppies are possible, though 50% of the litter may be carriers.

In a population where carrier rates are high (some French Bulldog lines have high carrier frequencies), it is not always possible to immediately eliminate the gene — but working systematically toward Clear × Clear breeding reduces it over generations.