Eye Testing - What's It All About

housebreaking_bell_trainingTo TEST or Not To TEST? - That is a very good question. What is it and why do it?  A certified eye exam is done by an ophthalmologist and checks for eye problems. Of course everyone knows that genetic testing is important in breeding stock but what about all the others and what about all the pets? At this time, heritable cataracts is a common genetic disorder in the Havanese. This is a somewhat unusual cataract. It cannot be defined as a Juvenile cataract; though it may appear as early as 10-12 months of age, it may also appear as late as 7 years of age. The most common age of diagnosis is 3-4 years of age. Therein lies the problem, as by that time an affected dog may have been bred a number of times and perhaps even to a second and third generation.

The very early onset form of cataract is the most disabling as it grows rapidly and may contribute to significant loss of vision, though it has been noted in many Havanese, that these cataracts progress quickly and then may break up and improve somewhat. A middle onset cataract shows up between 4-7 years of age. This type tends to be slower growing, it can progress, though usually quite slowly but it also can break up in subsequent years. This type is much less likely to cause blindness and minimally impacts the vision. This heritable cataract is not a senile cataract. Senior cataracts occur in most breeds in old age. In a long lived, slow maturing breed like the Havanese, these are unlikely to show up before 9-10 years of age.

The heritable cataract that affects Havanese appears to be a recessive gene where a dog must get the defective gene from both parents in order to become affected. At this time there is no test. Renowned ophthalmologist Dr Kirk Gelatt from the University of Florida is heading an on-going research study to isolate the gene, determine mode of inheritance and hopefully develop a test.

Until such time as a test is available, these heritable cataracts remain a risk for any Havanese. Eye testing remains the best means for us currently to identify this problem. Results of eye tests performed by Certified Veterinary Ophthalmologists can be registered with the  Orthopedic Foundation for Animals (OFA). Until recently, eye tests were mainly certified by the Canine Eye Registration Foundation - CERF.  Since June of 2014, eye certifications are through the OFA as CERF is no longer active in this capacity. Even though the Canine Eye Registry Fundation is no longer the main registry, you will continue to hear of an eye exam refered to as a CERF exam. 

Unlike many other one-time genetic tests, eye test results are only valid for a period of one year after which time the dog must be re-examined. When purchasing a Havanese, it is wise to choose a breeder who has all their dogs eye-tested yearly and to get a puppy only from two adult dogs that have current eye certifications.  Certified results of eye exams are not only for breeding stock and for show dogs. Havanese owners are urged to eye test any and all Havanese on a yearly basis including pets and companion dogs. The earlier any eye problem is diagnosed, the better chance there is of being able to treat it before blindness and/or eye damage occurs.

So what if one of your dogs fails? The more you know about this problem the better equipped you will be able to deal with it if it happens. Age of onset may matter as dogs afflicted at a younger age seem to have faster more aggressive conditions. Location of the cataracts is also important. While some do progress rapidly and may lead to blindness, others progress slowly with less visual impairment. Surgical intervention may be an option for more severe conditions. The earlier you become aware of any problem the better you can take steps to monitor progression and prevent/treat other associated problems that may develop. The importance of eye testing for all Havanese cannot be over-stressed. CHOOSE SIGHT! Eye-test your Havanese annually. Every Havanese that is tested adds to the genetic data base and knowledge we have about this serious hereditary condition and leads us one step closer to finding a solution so we can eliminate it from the breed.

Authored by: 
Suzanne McKay