The eyesight in our dogs changes with age.
Researchers based at the Nestlé Purina Research Center in Missouri have discovered that our dogs become more near-sighted as they age. Their results were published in the journal PLoS One.
This investigation used an instrument called an autorefractor to measure the dogs’ eyesight in indirect and direct lighting conditions. The study involved nine Beagles ranging in age from 1 to 14 years. Before entering the study, the dogs were examined to confirm that none of them had cataracts.
Measurements were taken on three different days of the week for a period of six weeks.
The researchers found a remarkable difference between the younger and older dogs. The older dogs had a much-reduced ability to see at longer distances (far-sightedness) compared to the younger dogs. Younger dogs were also able to make larger accommodation changes from indirect light to direct light conditions, indicating a more flexible lens.
Humans are the opposite in terms of length of sight. As we age it can become more difficult to read and see things at shorter distances whereas our ability to see at distances is often not affected (although some older people do have difficulties adjusting to night and low-light conditions, just as the dogs in this study did).
So if your dog is getting older and you notice that they can’t pick up on your body language and signals, there’s a physical reason for it.
Through my own experience working with older dogs, I recommend using a light that helps your senior dog adjust to low-lighting conditions. See my post on the PupLight, for example.
Kathleen Crisley, specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand
Here’s a photo of lambs ears that have been dyed using ‘human grade’ food coloring for Christmas. I have deep concerns about using coloring agents in dog (and human) foods.
For example, some dogs may be allergic or sensitive to the coloring agents. We know that the use of these additives can cause excitability since coloring agents have also been linked to hyperactivity in children.
Food colors are chemicals – they are just chemicals that have been tested by the FDA to ensure they are ‘safe’ for human consumption. Colors are added to make food more appealing and marketable.
Since our dogs have limited color vision and lack photoreceptors in their eyes to ascertain shades of red and green, the color added to dog treats is to appeal to the dog owner and not the dog. Dogs will decide if something tastes good!
How about some natural alternatives? Here’s a photo of my Chicken & Cranberry Holiday Crunch (a special for the holiday season). The red color is totally natural and comes from the whole cranberries that are part of the recipe.
Chicken and Cranberry Holiday Crunch
I recommend that you feed natural products whenever possible and avoid highly colored dog treats.
And remember that no more than 10% of your dog’s daily caloric intake should come from treats!
Kathleen Crisley, dog masseuse and nutrition adviser, Canine Catering Ltd
Posted in dog care, dog nutrition and labelling
Tagged additives, artificial coloring, artificial colouring, coloring agents, cranberries, dog treats, excitability, eyesight, food coloring, hyperactivity, lambs ears, marketing, photoreceptors
As a dog gets older, it is common that they will experience a loss of eyesight or visual acuity. I have found that many owners assume that their dog has cataracts but a more common problem is nuclear sclerosis.
Nuclear sclerosis, which is also called lenticular sclerosis, is a condition that causes the pupils of the eyes to look cloudy and often blue-gray in colour. Nuclear sclerosis isn’t painful and it comes upon the dog gradually. At some point you will notice that your dog isn’t seeing well at night and their peripheral vision may also be limited.
Such is the case with my Daisy. We have stairs that go from our house to the outside garden and I noticed that she would stop dead at the top of the stairs because she couldn’t see the steps in the dark. It made sense that, although I could turn a light on in the house, the lighting in the garden wasn’t as easy.
Then I found the PupLight, the lighted dog collar. Although marketed most strongly for people who walk their dogs at night and need to be visible to traffic, I decided to give it a try…
It’s been great! Just what we needed. I can clip the collar on before letting Daisy out at night and she can see the steps, and all the irregularities in the garden. And she adjusted to its use very well.
Daisy shows off her PupLight dog collar
The PupLight’s bright light makes it much easier for Daisy to see at night
Bottom line: Highly recommended product, particularly for senior dogs
Note: This product endorsement is entirely my own and was not paid for by the PupLight company or its retailers.