Yearly CERF Exams - Why Are They Important?
Sheryl Krohne, DVM, MS Diplomate ACVO, ACVO Genetics Committee/CERF Liaison
One of the most frequently asked questions at CERF is "Why is the CERF certification only valid for one year"? The reason is that some eye diseases in all breeds of dogs can occur at several ages. For example, if you take your dog to have a CERF examination when it is 8 weeks old, many diseases can be diagnosed. These diseases will not progress and once they have been diagnosed, they will not disappear or "go normal" in future examinations. These diseases include microphthalmos, iris coloboma, fundus staphyloma or coloboma, retinal detachment, persistent hyaloid artery, PHPV/PTVL, optic nerve coloboma, optic nerve hypoplasia, and micropapilla. Other diseases may be present at 8 to 10 weeks of age and these diseases can change in their appearance (get worse or better) or disappear with age. These include entropion and other eyelid conformational abnormalities, persistent pupillary membranes, retinal dysplasia (folds and geographic lesions), and choroidal hypoplasia. Still other diseases may not be diagnosed until the dog is older. Most hereditary cataracts do not form in the eye until dogs are 6 months to 8 years old. Progressive retinal atrophy is most commonly diagnosed in dogs that are 2 to 8 years of age, depending on the breed. The result is that a dog could be certified by CERF at 8 weeks and again as a 1 year old, and then not pass the CERF exam at 2 years of age because cataracts had appeared between the 1 and 2 year examination.
So, what does this mean to the breeder? Dogs should be certified every year to ensure that they have not developed serious ocular diseases that occur after dogs are one or 2 years old, such as cataracts or retinal atrophy. A yearly normal CERF exam would keep the dog’s CERF number up-to-date.
Individual dogs that are "clear" at their CERF exam at 9 years of age are usually not going to develop any genetic eye disease after 9 years. This is not completely true for every breed, however, it can be used as a general recommendation. My advice for show, obedience, performance, working and breeding dogs is that they have a CERF examination when they are young (< 4 months old), and another examination before they are used for breeding the first time. After that, males that are being used regularly for stud service should be examined every year until they are 10 years of age, and females and males that are being bred intermittently should be examined before they are bred each time.
Having the exam as close to the breeding as possible decreases the possibility that a genetic disease has appeared and will be missed before breeding again. Many females only have a litter every other year, and while a CERF exam from 11 months ago is still valid, it is not as useful to the breeder as an exam that is normal in the month before breeding. It is equally important to check the validity of the CERF number of the dog you are breeding your dog with. Many breeders accept the word of other breeders that their CERF clearance is current.
It is easy to check the date of the CERF examination on the VMDB/CERF website where the exam date is listed, along with the CERF certification number (http://www.VMDB.org). The CERF certificate also shows the year of the examination and the dogs age at examination, so you should ask to see the current certificate if you have not verified it from the website.
While yearly examinations do not guarantee that the dog is not a carrier of genetic ocular disease, they do ensure that within the last year, the dog was examined and no genetic ocular disease was diagnosed. If CERF clear dogs are bred, genetic ocular disease can be significantly decreased in each successive generation and eliminated in 6 generations.