DIRECTOR'S COMMENTS
Director: Walter Weirich, DVM, PhD
weirich@vet.purdue.edu
INSIDE
DIRECTOR'S COMMENTS
Director: Walter Weirich, DVM, PhD
weirich@vet.purdue.edu
The recent AVMA meeting brought many new and very interesting topics to the floor. One that seems to be the hottest (at least to me) is "evidence based medicine". What this means is that diagnoses are based on solid scientific evidence and treatments are based on what has been shown to work best in many patients with the same condition. This necessitates the ability to capture information on the diagnosis and treatment of many patients with the same condition that your immediate patient has. The problem in veterinary medicine is there is very little information of this nature available to refer to so that evidence can be generated to show what is the best, current treatment for a particular disease or condition.
Several things are happening that will allow the veterinary profession to embark on evidence based medicine. FIRST, SNOMED-RT a standard nomenclature, is scheduled for release in August 2000. Several years ago, the AVMA selected SNOMED as the standard nomenclature for the entire veterinary medical profession. The Standards Subcommittee of the AVMA Informatics Committee has been working on implementation of SNOMED-RT for the past several years. They have developed the means where data can be collected, stored in databases and retrieved for study. If treatment data is included in the data collected, then after a certain time when enough cases have been captured, the database can be searched and the most successful treatments can be sorted out for various diseases and conditions.
Several groups have been and are collecting data so databases of sorts do exist. But, these databases cannot communicate with each other in any reliable fashion. The SNOMED-RT nomenclature, when applied in a consistent fashion, will facilitate communication to take place and data can be shared. SECOND, software standards are being developed to effect the messaging within and between databases. This technology will be unseen by the user, but the messaging standards under HL7 (Health Level 7) are critical so that data transfers will be unambiguous.
Information is available from the Veterinary Medical Data Base with the first data being collected in April of 1964. Though it was collected with less than the best nomenclature and coding system, it is an excellent source of information on animal diseases and operations. Unfortunately, it has very limited information on treatment and treatment outcomes.
Efforts are being made to begin collecting teaching hospital data in the new format. Initial steps are being taken to establish data bases, which will collect, store and retrieve data from private practices. This has been a long process and it will take a little time before enough data is in the database to make them worthy of study. But, from this base of information, we will have the means to really practice EVIDENCE BASED MEDICINE.
Q: I made an error on my dog's name and/or registration number on the front of the form, can I white it out and correct it?
A: Do not change anything on the front of the form when you make an error, simply put the correct information on the back of the form along with a note explaining the error and/or a copy of the dog's registration papers.
Q: I don't want to include my dog's registration number on the exam for confidentiality reasons, do I have to?
A: The forms that you send in are completely confidential. The form that the ophthalmologist sends in is used for statistical purposes ONLY and cannot be retrieved by name or number. The form that you send in for certification MUST have the registration number on it for it to be CERF certified, however this too is confidential. We do send the CERF numbers over to AKC to be placed on the pedigrees, however the diagnosis is NEVER released to AKC or anyone else.
STAFF NOTES:
There have been many questions recently regarding the issue of permanent
identification of one's dog. In order for CERF and OFA information to appear
on a dog's pedigree, AKC has required the dog to be permanently identified
since 1996 and CERF will be requiring it as of January 2001. All dogs that
wish to obtain a CERF number must be permanently identified via tattoo,
microchip, or DNA profile number prior to CERF certification. We have
provided many of the ophthalmologists with scanners, however they can only
read HomeAgain microchips. If your dog has a microchip number from another
maker, please bring along a copy on this information to your appointment.
Some ophthalmologists are starting to perform microchipping in their office,
however if your veterinary ophthalmologist does not you would simply need to
have the dog microchipped or tattooed prior to sending in the exam for CERF
certification. I would also like to remind you at this point that simply
having your dog examined is not the same as having your dog CERF certified.
Please remember to complete the "owners" copy of the exam and send that in
to have your dog properly certified with CERF.
Collie eye anomaly (CEA) is a congenital, developmental defect of the eye. The disease has been reported in rough and smooth collies, Shetland sheepdogs, Australian shepherds and border collies. It was first described by Magrane in 1953 in the United States(*1) and has become very widespread in the collie breed. In the 10-year period from 1991-1999, 19,592 collies were reported to CERF by ophthalmologists and about 15,000 (77%) of these had some form of CEA. The incidence is lower in other affected breeds.
Collie eye is due to an abnormal development of the mesodermal (middle layer) tissues of the eye. This results in defects of the sclera, choroid, optic disk, retina and blood vessels of the retina. These defects can be very extensive and lead to blindness or they can be relatively minor and cause no visual deficits.
The most common form of CEA is choroidal hypoplasia (CH). This is a defect in the choroid or vascular system of the back of the eye. It can be seen in an ocular examination as a non-pigmented area beside the optic disk. Although CH causes no problems for vision it indicates that the affected dog carries the gene(s) for CEA. CH is a bilateral disease but one eye may be more affected than the other. The area involved is usually above and to the side of the optic nerve. Lesions of CH can be seen at 5 to 7 weeks of age but later can become masked by the development of pigment in the back of the eye as the dog ages. These cases are called "go-normals." It is because of these cases that it is important to examine puppies at a young age. Even though these dogs may appear normal as adults, they still are carrying the gene for collie-eye. CH does not become worse nor does it progress to any other type of CEA.
More severe cases of CEA usually have colobomas. In CEA, colobomas are depressions or excavations in the back of the eye and may involve the optic disk and/or the area around the optic disk. Colobomas may be seen by an ophthalmologist in puppies as early as 5 to 7 weeks of age. Colobomas may involve one or both eyes and may be very small and shallow or extremely large and deep.
Partial or total retinal detachments may be present in some cases of CEA. These may be unilateral or bilateral and usually develop in young puppies and cause complete blindness. Large optic disc colobomas can cause retinal detachment because the large "hole" in the back of the eye leads to accumulation of fluid behind the retina and pushes off the retina. Bleeding in the back of the eye can also occur in CEA and is thought to be secondary to colobomas and retinal detachments.
CEA is a known hereditary disease and is thought to be due to an autosomal recessive gene(*2). The site of the gene causing collie eye is currently being investigated(*2). Because of its hereditary nature, the policy of CERF is to recommend that any dog with CEA (of any severity) not be bred and affected dogs will not receive a CERF number. We hope that in the future a genetic test will be available to detect both affected and carrier animals and that this will help reduce the incidence of this disease.
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