# Eye exams and the BAER hearing test in dogs: what they detect and at what age they are done

https://casatrufa.com/en/blog/eye-exams-and-baer-hearing-test-in-dogs

By Casa Trufa · Published: 2026-10-09 · For information only: it does not replace a visit to your veterinarian

An eye exam is a check by a veterinary ophthalmologist for visible hereditary eye diseases; its certificate is valid for one year. The BAER test uses electrodes to measure whether each ear can hear, can be done from 35 days of age and is needed only once. Neither replaces DNA tests: they complement them.

## In short

- The eye exam looks at the eye as it is that day, which is why it is repeated every year.
- It does not detect carriers or diseases that have not yet shown; that is what DNA tests are for.
- BAER is the only accepted method for diagnosing congenital deafness, ear by ear.
- A dog that is deaf in one ear seems normal at home: only BAER detects it.
- In the Australian Cattle Dog, the Louisiana State University database records 14.6% of dogs with deafness in one or both ears.

## What is an eye exam for a parent dog?

It is a check of both eyes carried out by a veterinarian who specializes in ophthalmology, looking for hereditary diseases. The specialist dilates the pupil with drops and examines the eye inside and out with a slit lamp and an ophthalmoscope. The result is a dated certificate in the dog’s name.

There are two international reference schemes. In the United States, the [OFA](https://ofa.org/diseases/eye-disease/) eye registry only accepts exams by ophthalmologists who are diplomates of the American college (ACVO). In Europe, the [ECVO](https://www.ecvo.org/hereditary-eye-diseases/ecvo-hed-platform-und-ecvo-eye-examination-certificates.html) certificate is issued only by its diplomates and by examiners the college has assessed. To [issue it](https://www.ecvo.org/hereditary-eye-diseases/eye-examination.html), the animal’s registration document is required.

In Colombia, the breeding regulations of ACCC (Asociación Club Canino Colombiano, Colombia’s FCI member kennel club) do not name the eye exam among their requirements, and we could not confirm which certification scheme is used in the country. The reasonable thing is to ask who did the exam, what training they have and when they did it.

## What does the eye exam detect, and what does it miss?

It detects what can be seen that day: cataracts and defects of the retina, the lens or the eyelids. It does not detect what has not yet shown, or what a dog carries in its genes without being affected. OFA says so plainly: the diagnosis refers only to the observable clinical appearance of the animal.

It also has technical limits. OFA itself warns that it is a screening exam, not a complete check of the eye’s health: it does not measure tear production or intraocular pressure, so glaucoma, an early lens luxation or some cases of retinal atrophy can go unnoticed without additional tests.

That is why it is repeated. OFA certification **is valid for 12 months** from the date of the exam, and renewing it every year is recommended, because several eye diseases appear with age. A normal exam at two years old says nothing about five. In the Border Collie, the British [Royal Kennel Club](https://www.royalkennelclub.com/search/breeds-a-to-z/breeds/pastoral/border-collie) also asks for gonioscopy, which checks the angle through which fluid drains from the eye.

## How is it different from a DNA test?

One looks at the eye and the other looks at the gene. The exam sees diseases of any origin, but only once there is a lesion; the DNA test detects one specific mutation from day one, even in a healthy dog that only passes it on. They do not compete: each covers what the other cannot reach.

| | Eye exam | DNA test |
| --- | --- | --- |
| What it looks at | The eye, as it is that day | One specific mutation |
| Who does it | A veterinary ophthalmologist | A laboratory |
| How many times | Every year | Once in a lifetime |
| Does it detect carriers? | No | Yes |
| Does it see diseases that have no genetic test? | Yes, if they are already visible | No |

An example: progressive retinal atrophy usually shows signs at around three years of age or later. An affected dog can pass exam after exam while it is young. The DNA test would have flagged it as a puppy. Which test applies to each breed is covered in [genetic tests in dogs](https://casatrufa.com/en/blog/genetic-tests-in-dogs-cea-tns-mdr1-pra).

## What is the BAER test in dogs?

It is the test that measures whether a dog can hear, ear by ear. BAER stands for brainstem auditory evoked response: it records the electrical activity that a sound produces in the auditory pathway. According to [OFA](https://ofa.org/diseases/other-phenotypic-evaluations/congenital-deafness/), it is the only accepted method for diagnosing congenital deafness.

The [Louisiana State University School of Veterinary Medicine](https://www.lsu.edu/vetmed/deafness/baerexpl.php), which maintains a site devoted to deafness in dogs and cats, describes the procedure like this:

1. Very small electrodes are placed under the skin: one in front of each ear, one on the top of the head and one between the shoulders.
2. A computer delivers clicks through a foam earphone, one ear at a time.
3. The equipment averages the responses to many clicks to separate the auditory signal from the rest of the electrical activity.

It takes between 10 and 15 minutes and generally requires no sedation or anesthesia.

## At what age is the BAER test done?

From 35 days of age, which is the minimum OFA accepts, and only once: the result is valid for the dog’s whole life. Since a puppy should not leave its mother before eight weeks, there is plenty of time to test the entire litter before the puppies go home.

That changes what you can ask for. In a breed at risk of deafness, it is not enough for the parents to have their BAER: ideally each puppy has its own, because parents that hear well can produce deaf puppies. Where the test is done in Colombia is something we could not confirm from a public source; ask.

## What do unilateral and bilateral deafness mean?

Unilateral means the dog cannot hear in one ear; bilateral, that it cannot hear in either. For OFA, only a dog that hears in both ears passes. The practical difference is enormous: a bilaterally deaf dog is noticed early, but a unilaterally deaf one behaves at home like any other dog, and only BAER finds it.

That is why the test matters so much in breeding. A dog that is deaf in one ear lives well and, according to the [Louisiana specialists](https://www.lsu.edu/vetmed/deafness/genetics.php), can make a good pet; what it should not do is reproduce, because it passes on the predisposition just as a dog deaf in both ears does. OFA recommends not breeding from the affected animal and not repeating the mating that produced the deafness.

> [!CONSEJO] Ask for the BAER result in writing and check that it says what happened in each ear, not just “hears”. “He responds when I call him” is not a test: a dog that is deaf in one ear responds too.

## Which breeds should have a BAER test?

Those with pigment-associated congenital deafness. OFA links it to two color genes, merle and piebald (white spotting): where pigment cells are missing in the inner ear, the cochlea degenerates. Among the breeds on this site, the one that needs it most is the Australian Cattle Dog.

The data from [Louisiana State University](https://lsu.edu/vetmed/deafness/incidence.php) give a sense of scale:

| Breed | Dogs tested | Deaf in one ear | Deaf in both |
| --- | --- | --- | --- |
| Australian Cattle Dog | 603 | 11.8% | 2.8% |
| Border Collie (two British studies) | 4,143 and 2,597 | 2.0% and 2.3% | 0.4% and 0.5% |

In the [Australian Cattle Dog (Blue Heeler)](https://casatrufa.com/en/breeds/australian-cattle-dog), the breed club in the United States includes BAER among its recommended tests, according to the [American Kennel Club](https://www.akc.org/breeder-programs/breed-health-testing-requirements/herding-group-health-testing-requirements/). In the Border Collie the figures are low, but merle, one of the two genes OFA associates with deafness, exists in the breed. The responsible guideline is not to mate them. The reason is in the guide [merle Border Collie: colors and health](https://casatrufa.com/en/guides/merle-border-collie-colors-and-health).

Blue eyes, by the way, are not a diagnosis: they are common in color-linked deafness, but they do not indicate by themselves that a dog is deaf. You can see which tests each parent has in [Meet the parents](https://casatrufa.com/en/our-dogs).

> [!AVISO] This article is for information only. If you notice that your dog does not react to sounds, or has red, cloudy or half-closed eyes, consult your veterinarian, who will decide which exam is needed.

## Frequently asked questions

**What is the BAER test in dogs?** It is the brainstem auditory evoked response test. Using small electrodes, it records the electrical activity that a sound produces in the auditory pathway, and it does so in each ear separately. According to OFA, it is the only accepted method for diagnosing congenital deafness.

**At what age is a puppy BAER tested?** OFA accepts it in dogs at least 35 days old, and a single test is valid for life. That means the litter can be tested before the puppies go home.

**How often does a parent dog have an eye exam?** Every year. OFA eye certification is valid for 12 months from the date of the exam, because many eye diseases appear with age.

**Can a dog that is deaf in one ear be a good pet?** Yes. The specialists at Louisiana State University note that dogs with unilateral deafness can make good pets, but that they should not be bred, because they pass on the predisposition.

**Do blue eyes mean a dog is deaf?** No. Blue eyes are common in pigment-associated deafness, but they do not indicate deafness by themselves. The only way to know is the BAER test.

**Does the eye exam replace the DNA test for PRA?** No. The exam sees what is already showing; a carrier, or an affected dog that has no lesions yet, comes out normal. The DNA test detects the mutation before there are symptoms. The complete picture is having both.

## Sources

1. [Orthopedic Foundation for Animals (OFA): eye registry (CAER)](https://ofa.org/diseases/eye-disease/). Who examines, 12-month validity and limits of the exam
2. [European College of Veterinary Ophthalmologists (ECVO): the eye examination](https://www.ecvo.org/hereditary-eye-diseases/eye-examination.html). Procedure and equipment used in the exam
3. [ECVO: certificates of the hereditary eye diseases scheme](https://www.ecvo.org/hereditary-eye-diseases/ecvo-hed-platform-und-ecvo-eye-examination-certificates.html). Who may issue the certificate. We did not find the period of validity on this page
4. [Orthopedic Foundation for Animals (OFA): congenital deafness](https://ofa.org/diseases/other-phenotypic-evaluations/congenital-deafness/). BAER as the only accepted method, minimum age of 35 days, pass criterion
5. [Louisiana State University, School of Veterinary Medicine: what the BAER test is](https://www.lsu.edu/vetmed/deafness/baerexpl.php). How the test is done
6. [Louisiana State University: breed-specific deafness prevalence](https://lsu.edu/vetmed/deafness/incidence.php). Data for the Australian Cattle Dog (603 dogs) and British studies in the Border Collie
7. [Louisiana State University: genetics of deafness in dogs](https://www.lsu.edu/vetmed/deafness/genetics.php). Merle and piebald genes, blue eyes, unilateral deafness
8. [American Kennel Club: health tests recommended by breed clubs, Herding Group](https://www.akc.org/breeder-programs/breed-health-testing-requirements/herding-group-health-testing-requirements/). Australian Cattle Dog and Border Collie
9. [The Royal Kennel Club: Border Collie, breed health tests](https://www.royalkennelclub.com/search/breeds-a-to-z/breeds/pastoral/border-collie). Eye exam with gonioscopy and hearing test