Your Dog’s Vision

We have noticed a real decline in Rex’s vision for the last 6 months or so. He’s 13 years old, so we would expect a little change, but this seems like more than just a “little”. Our Vet took a look at his eyes a few weeks ago when we had him in for a vaccination. She said that although she is not an expert on dog vision, she felt there might be a problem as it appeared that Rex’s pupils were not responding to light as they should have been. We made an appointment with a Veterinary Ophthalmologist to find out what the problem is.

The Ophthalmologist appointment

It’s been a while since we have taken a dog to an ophthalmologist. I had this vision of a doggie ophthalmologist exam being similar to what happens to us when we go in for an eye appointment. I figured we would first see all that intimidating and scary looking instrumentation we see in our eye doctor’s office – containing meters, scopes, and whatever. Nope, there was nothing scary… just your normal vet examination room. I had to laugh… there really was an eye chart on the wall! Decoration only, of course. In some ways, the exam was very similar to what we would experience.

Dry Eyes

The first thing the doctor checked was to see if Rex’s eyes were dry. She did this by performing a Schirmer tear test. These tests are used on people too. The Schirmer tear test is when thin test strips, actually a type of wicking paper, is placed into each lower lid and held in place for about a minute. The paper turns blue as the wetness of the eye is absorbed. Then the amount of wetting is gauged via lines of measurement on the strips. Normal eye moisture is 15 – 25mm of wetting. Rex did not even flinch when this test was performed. I don’t really think he really felt the strips of paper in his eyes. His moisture content was in the normal range, which is good news.

Dry eyes in dogs are fairly common, unfortunately. There are several breeds that seem to have a predisposition for the disorder. Some of the more popular breeds are Westies, Pugs, Cavalier king Charles, Lhasa Apsos, Shih tzus, and Yorkies. Dry eye results from inadequate production of tearing. Tears work as a lubricant to the cornea. Lubrication helps to remove debris and possible infectious particles from the eyes. When sufficient tearing, or lubrication, is not present, it causes inflammation to the cornea and surrounding tissues. When this happens, your dog’s eyes may appear red and irritated. They may blink a lot. Sometimes they have a thick, yellowish discharge. Over time, the cornea begins scarring, reducing the dogs vision. It can be very painful and can lead to a complete loss of vision.

Intraocular Pressure

The next step in Rex’s exam was to check the pressure in his eyes. The pressure check is that test a human ophthalmologist does by propping our chin up in that “contraption” and then blowing a poof of air into the center of our eye. For dogs, many vets use a little instrument called a Tonovet tonometer to measure the intraocular pressure. It’s the coolest little instrument. The vet places the instrument directly in front of the dog’s eyes and presses a trigger. From the end of the instrument, a tiny stick with a ball on the end, technically referred to as a “probe”, pops out and “bounces” against the dog’s cornea. The tonometer slightly indents the cornea when it makes contact. The pressure that the cornea pushes back is what is recorded on a read-out atop the handle of the tonometer. Don’t worry… this happens in a nano-second. Again, Rex didn’t even flinch. Actually, these same instruments can be used for people too, but we usually see more sophisticated instrumentation in human doctor’s offices.

Checking the pressure in your dog’s eyes, and in human eyes, for that matter, is the most efficient way to check for glaucoma. Glaucoma happens when the pressure in the eye is higher than normal, producing inadequate fluid drainage. The disease can be caused by a predisposition to the disease, trauma, or as a consequence of another other eye problem that affects the optic nerve. It’s painful. The dog may suffer from pain not only in the eye, but throughout its entire head.

What should we look for to determine if our dog might be developing glaucoma? Redness, irritation, cloudy cornea, tearing, and vision problems. As the disease progresses, the dog’s eyes may look to be “bulging”. If left untreated in one eye, it can eventually infect the other eye. If the disease is caught early enough, treatment and medication can prevent further damage. Sadly, when the disease has progressed past the point of treatment, it may necessitate the removal of the dog’s eyes.

For whatever reason, there are many dog breeds that are susceptible to glaucoma. Some of the more popular include Akita, Poodle, Cocker Spaniel, Springer Spaniel, Basset Hound, Beagle, Shih Tzu, Boston Terrier, Miniature Pinscher, and Miniature Schnauzer. Poor things.

We were very pleased that Rex’s intraocular pressure was normal.

Cataracts

In April this past year, we published a blog entitled “Caring for your senior dog“. In the blog, we stated that the clouding of an aging dog’s eyes (aka nuclear sclerosis) is a normal progression and does not necessarily indicate a problem. This is true, but to an untrained eye, how do we differentiate between cloudy eyes and eyes affected by cataracts? We can’t. Only our veterinary can tell us for sure.

Perhaps I had become too comfortable with thinking that Rex’s cloudy looking eyes were normal. I was surprised to learn that fairly large cataracts had developed in both of his eyes. They were very visible when the doctor shined a light onto his eyes. It made me sick. Fortunately, cataracts can be removed. However, had I possibly been more vigilant in caring for his eyes, we may have been able to avoid surgery, which is never fun for the dog. Just like people, a dog’s eyes will often develop cataracts, particularly as they age.

Cataracts obscure a dog’s vision. They can be as small as the tip of a pin, or large enough to cover the entire lens. Cataracts do not hurt, but sometimes they can cause inflammation, which could be somewhat uncomfortable. One of the main reasons dogs develop cataracts is because of the UV rays of the sun. I have often thought that Rex should be wearing sunglasses when we were outside, but never seriously considered buying them. I mean, how many other dogs do you see with sunglasses on? Cataracts can also develop from high blood sugar. And once again, heredity plays a huge role in the development of cataracts, often seen in Yorkies, cocker spaniels, Fox terriers, and others. When heredity is a factor, cataracts can develop as early as 1 year old.

PRA – Progressive Retinal Atrophy

When we first adopted Rex several years back, his veterinary at that time was quite certain that he had PRA, Progressive Retinal Atrophy. We were very disturbed by this prognosis because there is no treatment or cure for the disease. PRA is a degenerative eye disease whereas the cells of the retina deteriorate, leading to severely impaired vision or blindness. In fact, our vet informed us emphatically that Rex would be blind within a year. A second opinion, however, concluded that Rex had no problem with his vision.

Because of the uncertainty, we quickly scheduled a consultation with a Veterinary Ophthalmologist who confirmed that Rex did not have PRA. The Ophthalmologist said, quoting, “Looks like something is ‘going on’ with his retina, but it’s not PRA.” We were relieved. In hindsight, “something going on” with his retina should have clued us in to continue regular ophthalmologist checkups.

The only reason given for the cause of PRA is genetics. Some of the breeds most affected in varying degrees are Corgis, Collies, Irish Setters, Cocker Spaniels, Dachshunds, Labradors, and Poodles.

Sudden Blindness

There is one other rarely mentioned vision condition called in dogs called “SARDS”, Suddenly Acquired Retinal Degeneration Syndrome. It’s an odd condition in that symptoms are not always eye-related. An increase in thirst and/or appetite, lethargy, weight gain and changes in urinary habits are some of the unusual symptoms seen in SARDS affected dogs. The most distressing thing is that once these symptoms are detected, blindness quickly follows – within a couple of weeks!

In SARDS, the rods and cones within the retina just suddenly die. Period. Weirdly, the retina looks normal when examined under typical ophthalmological instrumentation, even though significant damage has already occurred. Although this disease has been known about for about 20 years, even now, there is no established cause. The disease has been associated with autoimmune disorders, allergic causes, and even exposure to toxins, but still, nothing concrete. There is no way to predict if your dog will succumb to SARDS. This has to be a very frustrating syndrome to both the pet parent and the veterinary.

Lens Luxation

Lens luxation is when the lens of your dog’s eye(s) become detached. It can be either partially or fully detached. Lens Luxation happens when the zonules, the fibrous strands that hold the lens in-place, degenerate. It usually occurs in both eyes. It is a serious, painful, and blinding condition. Surgery is the only “treatment”, either to preserve the vision if at all possible, or to simply make the dog more comfortable when any type of preservation or correction is not possible.

Lens luxation is most often seen in Border Collies, Australian Cattle dogs, and terrier dog breeds, but is not just a hereditary disease. It can be caused by other eye issues such as cataracts, glaucoma, or other types of inflammation within the eye.

Final Thoughts

Our Ophthalmologist believes that Rex only has far vision in one eye, and no nearsightedness at all. He is completely blind in one eye. He was put on anti-inflammatory eye drops and a vision supplementation. We are to see the ophthalmologist in two months to determine whether or not it is even feasible to operate to remove cataracts. If removing cataracts will maintain whatever vision he has currently then we are all for it. If there is no “life” behind the cataracts, and if he has no discomfort as a result of the cataracts, there is no need for surgery.

If I could turn the clock back, I would do anything to help keep Rex’s vision as sharp as possible and his eyes as healthy as they can be well into old age. If your dog’s breed was mentioned as having a predisposition to any of the above disorders or diseases, we recommend you begin regular eye exams while your dog is still a “young adult”. For other breeds, do some research, as it was not possible to list all breeds in this blog. If at any time you notice any changes in your dog’s eyesight or in the look of his/her eyes, please don’t hesitate to talk to your veterinary.

Note: If your dog has limited or no sight following one of these medical occurrences, our Holiday Barn Pet Resorts’ Professional Dog Trainers can help your dog more readily adjust to his environment by working with him and your entire family in the comfort of your own home. Our Trainers will help your dog with spatial awareness of their surroundings, and then help you with properly guiding the dog so that they do not injure themselves, both in the home and outside of the home.