by Anne Jones RN, BSNE
It was a shock to find the first few reports of SARDS in Bichons because this seemed to be a new malady for the breed. Upon investigation it became clear that some of the instances of sudden blindness that had been reported may have been SARDS instead of cataract generated blindness or retinal detachment. While we see only one or two reports a year of an affected Bichon, we do need to make breeders and Bichon owners aware of the condition. Unfortunately there is no treatment and it may or may not be genetic.
SARDS stands for sudden acquired retinal degeneration syndrome. There is little if any advance warning that the dog is afflicted until the dog starts to run into objects, though in some instances the progression may begin a week or two before total blindness occurs. The pupils will appear normal but are not reactive to light and are dilated. The condition is a sudden death of the cells (rods and cones) that enable the eye to see. These same nerve cells are the ones affected by PRA (progressive retinal atrophy) but these appear to be distinct and different conditions.
Indications are that this is a disease of middle-aged and older dogs and there are more reports in females. Onset may be related to stress and there may be a connection to onset of Cushings but this has not been proven to date. Increased thirst and hunger would suggest there may be a relationship. Because the loss of vision with SARDS is so acute, the dog often appears confused. Early ERG examination (electroretinogram) shows no changes in the appearance of the retina but the reading is “flat” indicating profound outer retinal damage. The ERG remains unchanged over time. Hence the diagnosis of SARDS is usually based on normal appearing ocular fundus (the back portion of the interior of the eyeball, as seen with an ophthalmoscope) with a “flat” ERG.
With early PRA some ERG recording is possible. The onset of the loss in vision spans from a few days to a few weeks and involves both day and night blindness. Early PRA primarily affects night vision first and advanced PRA causes blindness. In SARDS, later ERG will make it appear that the dog has PRA. Remember that PRA has gradual onset while SARDS is virtually instantaneous. There do not seem to be the same complications with SARDS as in PRA in that there is no uveitis (inflammation of the iris and ciliary body of the eye) or development of secondary cataracts. Diagnosis can only be made by a veterinary ophthalmologist and an examination should be done as quickly as possible to differentiate from PRA.
There is no treatment for the condition, which does not seem to be painful for the dog, and the dog will not recover her vision. Her distress results from the suddenness of the attack. In cataracts and PRA, the loss of sight is gradual and the owner needs to understand the confusion that the dog must feel to be instantly blind. With other conditions, the dog has had a period of adjustment as vision fades and she can adapt to the dimness and eventual loss of sight. With SARDS, the pet needs help to overcome the disability and her owner should be careful to keep her in familiar surroundings. Initially the sense of smell and hearing seem to be diminished but these other senses will sharpen with time and enable her to find her way around.
It should be understood that other maladies may cause blindness and can be treated. Some of these are optic neuritis (treated with anti-inflammatory drugs); brain tumor or tumors pressing on the optic nerve (treated with radiation); and possibly elevated blood lipids associated with changes in blood pressure. Differential diagnosis can be made by testing for those conditions. Nevertheless the flat line ERG is the specific diagnostic result that will confirm SARDS when these other tests have come back as negative. Again we would stress the need for ERG to be done early rather than later so as not to confuse the findings with PRA, a genetic condition.
In response to several questions in regard to SARDS, we received the following response from Dr. Kirk Gelatt: As to your questions, SARD is not breed specific nor inherited. It is primarily in middle aged female dogs. Bichon PRA is not as common as cataract; probably by a factor of 1 PRA to 100 cataracts or more. SARD has been associated with liver, pancreas, and adrenal gland abnormalities. However, still no single association and often SARD dogs have normal blood chemistries. End-stage SARD is difficult if not impossible to distinguish from advanced PRA. While Dr. Gelatt’s answers provide more questions to be asked, they do show that this condition is not yet fully understood by veterinary ophthalmologists. Is there a relationship to PRA? Is this a disease that will continue to increase among Bichons? We hope that you will be alert to this sudden cause of blindness and report any dogs that are diagnosed to enable us to track it’s progress in our breed.
For more information on SARDS, see www.sardsawareness.org. This web site has a hyperlink, titled Dealing with a Blind Dog, that may be helpful. To assist the BFCA Health committee in understanding the implications for Bichons, please report any Bichon diagnosed with the condition to the Health Committee. We already know that there are many Bichons with Cushings syndrome so it is likely that the numbers of SARDS affected Bichons may increase if there is indeed a relationship.
Information for this article comes from the above mentioned web site, an article in YOUR DOG, April 2004, Volume X, Number 4 and various other texts. Additional information has been provided by Dr. Kirk Gelatt, University of Florida, who is quite familiar with eye diseases in Bichons. Our thanks to Dr. Gelatt for his continued interest in our breed.
Important new information on treatment:
According to the following web site, there is the possibility of restoring some vision to dogs afflicted with SARDS. You need to read the report found at www.caninecushings.net/forums/showthread.php?p=36766 for more information. You may also want to print out the article there for your veterinarian or veterinary ophthalmologist to read if they have not mentioned the possibility of this treatment to you. While we have learned of this new treatment, we make no guarantees that it will be successful for you Bichon but you should have the information in order to explore and find out more about it. Please understand that it is important that you pursue this immediately because delay may mean the treatment cannot succeed.