Any dog can go blind but fortunately this can sometimes be prevented. Caroline Zambrano discovers how to tell if your dog has vision loss and how quality of life is not compromised by darkness.
Raj, a three-year-old Akita, loved chasing ball and played regularly with his owner. One day, his owner threw the ball across to Raj but he didn’t even notice. Raj went for an examination at Melbourne’s Animal Eye Care clinic, where veterinary ophthalmologist Dr Robin Stanley discovered that his pupils were larger than normal and that they did not respond to lights.
A deeper eye exam revealed bilateral retinal detachments, where the back part of the eye (retina) separated from the underlying, vascular part of the eyeball (choroid), which could be a sign of glaucoma, high blood pressure, exposure to certain toxins or a hereditary condition, Dr Robin explains. “We checked Raj’s blood pressure and blood tests were all normal. Some large-breed dogs have inflammation that causes the retina to detach and cortisone can help reduce this inflammation. We started Raj on oral cortisone,” the vet says.
In the meantime, the Akita didn’t cope too well to living in sudden darkness. “Being a large, active dog, Raj was bumping into things a lot. His owner didn’t cope too well, either,” Dr Robin says. “The good news is that within five days, Raj’s vision was back to normal!”
Dr Robin, who has been working in ophthalmology for more than 30 years and is the first veterinary eye specialist to be trained in Australia, says vision loss is a common canine eye problem caused by a number of reasons, including poor breeding and chronic health conditions.
“Unfortunately, we see a lot of inherited defects that can cause blindness. Responsible breeders will have their breeding dogs checked for genetic eye diseases,” he says.
If you are interested in getting a purebred dog, ask the breeder if they had their breeding dogs’ eyes checked. This shows a breeder who
is keen and aware of inherited eye diseases, Dr Robin says.
Some cases of vision loss are related to diabetes — increased sugar levels, which cause cataracts to form. Veterinary ophthalmologists are also seeing sudden vision loss due to retinal inflammation (reaction in the nerve tissue) and SARDs (sudden acquired retinal degeneration), which is incurable, Dr Robin explains.
Dogs of any breed and age can become blind. Some of the inherited eye conditions can be present at birth or develop shortly after, but more commonly between five and eight years of age. “We often see cataracts in young Cavaliers, Bichon Frises and Miniature Schnauzers,” the vet says.
Some dogs are born blind due to a genetic eye disease, such as retinal dystrophy but, fortunately, congenital eye problems from birth are rare in Australia, Dr Robin says.
Untreated eye infections can also cause blindness. Conjunctivitis is a common problem in dogs that can be caused by dry eye, a lack of tears. “Tears are very important in providing nutrition to the cornea. Without tears, many dogs will develop corneal scarring and this can result in blindness,” he says.
What is PRA?
Progressive retinal atrophy (PRA), an inherited disease seen in a wide range of dogs, is the most common cause of inherited vision loss and is usually presented with poor night vision, Dr Robin explains. Breeds most commonly affected by PRA include Labradors, Australian Cattle Dogs, Poodles and Cocker Spaniels.
Other very important common eye diseases include cataracts (cloudy lenses) and glaucoma (increased eye pressure), Dr Robin says.
“Small, white fluffy dogs” (ie Maltese) are also prone to developing sudden vision loss in middle age commonly due to inflammation in the retina,” he adds.
“Older dogs — like older humans — are prone to developing senile (age-related) cataracts. We also see poorer close-up and have poorer night vision due to ageing changes in the lens.”
Diabetes — an obesity-related but mostly hereditary disease — can also cause blindness in dogs. Dr Robin, who performs cataract removals in two to three diabetic dogs a week, says diabetes seems to be increasingly common in dogs. Unfortunately, vision loss is not reversible with diabetes treatment.
“Once the increased sugar gets into the lens, the sugar is metabolised to sorbitol and this causes the cataract to form. In humans, cataracts can take years to develop but in dogs, particularly diabetics, the cataracts can develop very quickly,” Dr Robin explains.
Responsible breeding is key
With many inherited eye diseases, little can be done to treat blindness once breeding has taken place.
“To prevent ongoing problems, breeders need to be aware of what eye problems occur in their breed, review their own breeding and have their breeding dogs’ eyes checked. And if you ever have a dog with eye problems, let the breeder know,” Dr Robin says.
Many Australian National Kennel Council breed clubs are proactive about health-checking their dogs’ eyes and run regular veterinary eye examination days through the Australian Canine Eye Scheme (ACES) (ava.com.au/aces). Dr Robin is one of the assessors for ACES and believes the scheme is valuable for breeders and ultimately the dog owners.
“One of the important things that the ACES does is produce reports of the findings for each breed. I think this is very important as it can be used to help breeders work out any problems they have,” he says. “We have many breeders who organise group bookings and on these days, we might have 10 to 40 dogs being checked. The dogs and their owners find this an enjoyable social experience.”
Improving quality of life
Dogs that develop vision problems adjust to blindness over time, Dr Robin explains. “In our experience, there is a period of disorientation and reorientation that lasts about two to three weeks. However, after this time, anxiety and confusion lessen greatly,” he says. “Dogs begin to rely more heavily on their other senses, such as hearing and smell, to help them get around. In fact, there also seems to be some sort of ‘radar’ that helps dogs navigate their environment.”
Until a dog learns to negotiate their territory, here are some tips from Dr Robin:
- • Keep the environment as stable as possible, ie keep furniture, food and water bowls in the same position
- • Educate small children about approaching the dog without startling him
- • Supervise your dog’s exercise, especially in unfamiliar surroundings
- • If you have other pets, place different-sounding bells on their collars so your dog knows where they are
- • Ensure your dog does not have access to roads and traffic, or the backyard pool!
- • Place barriers to stairs and stair landings — at least until your dog learns how to use these
“In my experience, most dogs cope extremely well; it’s the owners we worry about,” Dr Robin says. “One of the great things about working with dogs is that they make the best out of every situation. They just get on with it and use their other senses.”
Dr Robin says vision loss doesn’t cause pain and dogs do not need to be put to sleep because they are blind. In fact, “a recent study surveying owners of blind dogs found that many owners felt their relationship to their dog improved and the majority of owners perceived their dogs to have a moderate to excellent quality of life,” he says.
How can you prevent your dog from losing his vision? Examine your dog’s eyes regularly. Look for any changes in colour of the eyes, squinting or increased discharge, Dr Robin advises.
“Although most cases of diabetes are genetic, it’s important to keep your dog at a healthy weight and feed a quality/appropriate diet,” he adds.
If you are concerned about your dog’s vision, speak to your veterinarian who will be able to diagnose blindness and can refer cases to veterinary ophthalmologists as required.