I am continuing my canine health screening series with the eye screening exam (sometimes referred to as a CERF exam).

What Is The Purpose Of The Eye Exam And How Is It Done?

The eye exam is a screening exam that provides a breeder with information about whether a dog may have inheritable eye diseases.  This allows the breeder to make informed breeding decisions.

The exam is performed by board certified (ACVO) veterinary ophthalmologists.  The dog’s eyes are dilated and the exam is preformed using indirect ophthalmoscopy and slit lamp biomicroscopy.

It is not a comprehensive ocular health examination, but rather an eye screening exam.  The ophthalmologist is looking for specific genetic disorders that frequently result in blindness.  If any of these disorders are present, the recommendation is against breeding that dog.

Source

What Are The Disorders For Which There Is A Recommendation Against Breeding In All Breeds?

1. Keratoconjunctivitis sicca (KCS) – Breeding is not recommended for any animal demonstrating keratitis consistent with KCS. The prudent approach is to assume KCS to be hereditary except in cases suspected to be non-genetic in origin.
2. Cataract – Breeding is not recommended for any animal demonstrating partial or complete opacity of the lens or its capsule unless the examiner has also checked the space for “significance of above cataract unknown” or unless specified otherwise for the particular breed. 
3. Lens luxation or subluxation.
4. Glaucoma.
5. Persistent hyperplastic primary vitreous (PHPV)
6. Retinal detachment.
7. Retinal dysplasia – geographic or detached forms.
8. Optic nerve coloboma.
9. Optic nerve hypoplasia.
10. Progressive Retinal Atrophy (PRA) – Breeding is not advised for any animal demonstrating bilaterally symmetric retinal degeneration (considered to be PRA unless proven otherwise).

*Note: The prudent approach is to assume these disorders are hereditary except in cases specifically known to be associated with trauma, other causes of ocular inflammation, specific metabolic diseases or nutritional deficiencies.

Dogs with these disorders are not eligible for an Eye Registry Certification Number and the recommendation is that they should not be bred.  Source

How Does A Dog Receive A Certification Number?

A dog with a normal test result will receive an Eye Registry Certification Number.  There are also several conditions which may be noted as “breeder option”.  It is suspected these conditions are hereditary, but they won’t normally compromise vision.  The dog is technically “passed” and will receive an Eye Registry Certification Number with the condition noted.  It is the breeder’s option whether to use the dog as part of their breeding program.   A list of the “breeder option” conditions can be found here.

The exam result is valid for one year and should be repeated prior to breeding if the exam is more than a year old.

What Is The Difference Between Eye CERF And OFA Eye Registry Certification?

Both CERF and OFA maintain eye registries of test results.  The tests are the same and they are both conducted by board certified (ACVO) veterinary ophthalmologists.  The forms the doctors use to record their exam results are different, but both registries will accept the other registry’s form.  It is the breeder’s option which registry to use.

How Should A Puppy Buyer Use This Information?

Eye exams are one of the least expensive health screening exams.  Many dog shows offer clinics where the exam is priced at $35 or $40 per dog.  Most are first come first served during the clinic hours and are usually offered on multiple days.

The test is quick and painless for the dog but the results can alert breeders and puppy buyers to hereditary conditions present in the parents which may affect the puppy’s vision.  Puppy buyers should ask for a copy of the sire and dam’s (dad and mom’s) registration and verify a normal result, or if not normal, a breeder option result.    Puppy buyers can also verify the sire and dam’s test results through one of the public registries, either the CERF or OFA registries.  Puppy buyer’s should also verify that test result is current, (within a year of the breeding).

The Eye Exam–One Pup’s Experience

Freighter had his eyes examined at the show he attended this past January.  We paid the fee and then drops were put in his eyes to dilate them.  While we were waiting for his eyes to dilate, we filled out his paperwork.

It is necessary to bring all pertinent information and numbers along to the exam, including the dog’s AKC registration number and microchip number, if any.  Once the paperwork was completed, the clinic workers verified Freighter’s microchip number by scanning it.  Then we waited for our turn.

The exam is conducted in a darkened room.  The dog should hold still which can be a bit tricky since the ophthalmologist uses an unusual looking piece of equipment to look in the dog’s eyes.  Most vets are used to dogs who are uneasy so they go slowly.

Freighter can be one of the wiggly pups, but eventually the vet was able to finish the exam.  His eyes were normal.  This is actually his second exam.  He had his first eye exam in January 2013 and also received a normal result.

My next post will some general information and observations about DNA testing.  This is a whole new area of testing and presents many benefits, but also many challenges.