Researchers at Cornell University have found that there is a neurological link between a dog’s sense of smell and their vision. This study shows that a dog perceives his environment using both vision and scent. This is the first time that scientists have found a neurological connection of this nature in any animal.
In addition, scientists have found that dogs have connections between areas in the brain that process memory and emotion which are similar to humans but that they also have connections between the spinal cord and the occipital lobe which are not found in humans.
This finding explains why blind dogs are able to function, being able to play fetch and navigate their surroundings much better than people with similar blindness. That is comforting for people who own dogs who are blind or have gone blind.
Author’s Note: Although blind dogs can find their way around better than people, it is still a good idea to not move furniture around. If you have to move or add furniture, you can put a unique gentle scent on the corners of the furniture at the dog’s level to help the dog locate and identify the new or moved object.
We also have to think about how the relationship between scent and vision affects dogs in terms of training and their reaction to the environment, taking into consideration personality traits such as friendliness, fear, aggression etc. While we know that many of the personality traits of dogs are inherited, is it possible that these findings might explain further exactly how and what is inherited. Many people do not realize how complex dogs and perhaps other animals are.
The researchers have discovered that this recessive gene, which blocks the developing eyes of puppies from getting vitamin A, causes blindness. In order for the disease to occur, both the mother and puppy must have the mutated gene, which is why all puppies are not born blind.
It has also been determined that the RPB4 gene may be related to human MAC disease. So again, understanding canine diseases may lead to cures for humans.
An Irish Soft-coated Wheaten Terrier, Photo: Lohi Research Group
The good news is that researchers have developed a DNA test that can identify those dogs that carry the gene. This will help both veterinarians and breeders control and hopefully eradicate blindness in this breed.
Over the past three years, veterinarians have continued to work with blindness in dogs. They have succeeded in curing X-linked retinitis pigmentosa when caught early. XLRP causes gradual vision loss starting at a very young age in dogs, often as early as five weeks of age. It is an inherited retinal disease.
Continuing the research using the same techniques, the researchers found that the gene therapy helped dogs at 12 weeks of age (mid-stage disease) when about 40% of the eye’s photoreceptor cells were dead and then at 26 weeks of age (late-stage) when 50 – 60% of the cells were dead. What the researchers found was that they were able to halt the degeneration of the photoreceptor cells in the treated area.
A few years ago, a team from the University of Pennsylvania announced that they had cured X-linked retinitis pigmentosa, a blinding retinal disease, in dogs. Now they’ve shown that they can cure the canine disease over the long term, even when the treatment is given after half or more of the affected photoreceptor cells have been destroyed.
To date, dogs have maintained their vision for over two years after treatment. This is very exciting because humans suffer from the same type of blindness. With that in mind, researchers are already examining human patients to determine how to treat their blindness and who might qualify for future treatments.
Again, man’s best friend is offering hope to humans who suffer from this type of cell death that causes blindness. Since this is an inherited disease, breeders should have their dogs examined by a certified canine ophthalmologist and register their dogs with the Canine Eye Registration Foundation, CERF. http://www.tctc.com/~maplerg/cerf-.htm This will help researchers continue to develop cures for blindness as well as prevent the breeding of dogs who have this inherited disease.
Both dogs and humans suffer from blindness caused by Leber congenital amaurosis, or LCA. Researchers have recently discovered that the disease is has similar causes in both humans and dogs.
According to Dr. Gustavo D. Aguirre of Penn’s School of Veterinary Medicine, this information opens the door to developing therapies to halt or cure this form of blindness. The Penn team made an important discovery, although the dogs lack functional vision in daylight, the cone cells are still there even though they are very compromised.
The hope is that they can develop a therapy to stop the degenerative process and possibly reverse it. According to Dr. Aguirre they already have had success with preliminary gene therapy that indicates that this would be possible.