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Health Testing Guide
Which tests matter, how to spot responsible breeders — and what it costs when things go wrong.
For the Sealyham Terrier we've compiled 1 test in the recommended health standard and 3 additionally recommended tests, drawn from veterinary databases such as CIDD (University of PEI) and OMIA — weighted by severity and heritability.
View verified breedersWhat this grade means
The Sealyham Terrier shows an overall solid health profile with a manageable number of hereditary diseases. Nevertheless, buyers should pay specific attention to eye health, as conditions such as retinal dysplasia (RD) and the painful primary lens luxation (PLL) occur in the breed. In addition, congenital deafness can occur in rare cases, which is why an early hearing test for the puppy is advisable.
Every breed is susceptible to certain inherited conditions. Just like humans, dogs inherit predispositions from their parents. Responsible breeders screen their breeding dogs for these conditions and make informed mating decisions to reduce the risk passed on to puppies.
No — but it's the strongest tool we have. Diet, exercise, environment, and genetics all contribute to whether a dog develops a condition. When breeders use the right tests to identify risk in potential parents, the likelihood of many conditions appearing in the puppies drops significantly.
There's no one-size-fits-all here. The recommended health standard for the Sealyham Terrier covers 1 test, plus 3 additional recommended tests. The specific tests and passing thresholds are detailed further below.
Keep in mind
Reliable screening tests still don't exist for many hereditary conditions, and tests for complex polygenic conditions don't always predict severity in the puppies. Even so, they're a powerful tool of responsible breeding.
There are two main types of health tests:
Screen the dog's DNA for known disease-causing mutations. Can be performed from puppyhood and give a binary result (clear / carrier / affected).
Clinical and imaging exams like X-ray, ultrasound, or ophthalmoscopy. They show how a predisposition actually manifests — usually only conclusive after 12–18 months.
We group breeding programs into three levels based on testing depth. Ask your breeder directly which level they meet.
A breeder at the Great level meets the Good level and performs 3 additional clinically recommended screenings that reduce risk in this breed.
In addition to Good:
Keratoconjunctivitis sicca (KCS) - "dry eye"(KCS)
Augen
Keratoconjunctivitis sicca (KCS), commonly known as dry eye, is a chronic disease of the ocular system where the tear glands fail to produce enough natural tears. Without this protective moisture, the cornea (the clear surface of the eye) and surrounding tissues become dry, inflamed, and highly susceptible to painful damage.
Eye examination · Passing: clear
Lens luxation(PLL)
Augen
Lens luxation is an inherited eye disorder where the lens slips out of its normal position because the supporting fibers holding it in place weaken or break. When the lens shifts, it can block the natural drainage of fluid within the eye. This blockage causes a rapid, painful buildup of pressure called glaucoma, which can lead to permanent blindness if left untreated.
Eye examination · Passing: clear or carrier
Congenital deafness(CHSD)
Nervensystem
Congenital deafness is a hereditary hearing loss present from birth that affects the inner ear's sensory cells, preventing sound signals from reaching the brain. It is usually genetic, occurs more often in certain breeds and is frequently linked to coat patterns such as merle or piebald.
Physical examination · Passing: hearing in both ears
These levels are a comparison framework, not an official certification. They help compare breeding programs at a glance.
A complete checklist with every core-standard and additionally recommended test, plus identity and rearing questions — take it with you.
Open the full checklistFor breeders
Machine-readable mating rules, minimum ages, scoring schemes, and what's required for HonestDog verification — as a printable guide.
Example rule — Retinal Dysplasia
Both parents must be clear or better.
We take mandatory tests from official breed regulations, build the recommended health standard from veterinary databases — and cross-check every uploaded certificate against the dog's profile using AI.
L1 = core standard: the club's required tests where its rules set them, otherwise the recommended health standard for the breed. L2 = additionally recommended or clinically indicated. L3 = lower prevalence. Every assignment carries a source and confidence rating.
VDH breeding regulations, CIDD (University of PEI), OMIA (University of Sydney), curated veterinary input.
Uploaded certificates are read by AI and checked for date, result, and consistency with the dog's profile — our team reviews anything inconclusive.
The Sealyham Terrier is not currently listed in our extreme-breeding overview. That does not mean it is free of hereditary disease: which ones are typical, and which tests the parents should have, is on this page.
Self-check
Answer 6 quick questions about your everyday life and see how well the Sealyham Terrier fits you — including an honest cost estimate per month, per year, and across the dog's lifetime.
See breeders who have already uploaded their health test results for verification.
View verified breeders