SIGHT
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A dog is ten times more sensitive to
peripheral movement than we are. He picks up movement on either side of him
better than we ever could, in part because most dogs’ eyes are closer to the
sides of their heads than ours are. A dog’s vision is poor up close, but he can
see quite well at a distance.
♦ Anatomy of the Eye
The dog’s eye is different from ours.
Our eyes are better at defining detail in bright light. The dog’s eye has a
reflective layer that intensifies light and helps the dog (as it did his
predecessor, the wolf) to see more when he needs it most: for hunting at dawn
and dusk. At night, when you see a car’s headlights reflect brightly off a
dog’s eyes, what you are seeing is that reflective layer. Dogs can see in low
light but they cannot see in the dark—they do not have the mechanisms that a
cat does to allow that.
Dogs see in black and white when
there is low light, but when it is brighter they do see some color.
♦ Sight Hounds
Some dogs have very good eyesight
because the work for which they were originally intended required great vision.
Many retrievers and the so-called sight hounds—for example Salukis and their
descendants like Afghan Hounds, Borzois and Greyhounds—have amazing vision.
These dogs have frontally placed eyes, as people do.
Many terriers have slanted
eyes—they’re physically frontal, but the slant allows them to see around
corners.
Guardian dogs like German Shepherds
and Akitas have more laterally placed eyes.
There are also many breeds that
depend much more on their sense of smell and even on their hearing, so their
vision is unremarkable.
♦ Blindness
“Progressive retinal atrophy” is an
inherited blindness that can strike dogs in breeds that are at risk for it.
There are times when people think an otherwise healthy dog is going blind
because they notice that she cannot see a toy “right in front of her.” However,
the inability to see something “right in front of her nose” is not a cause for
concern, because due to where a dog’s eye is placed on her head, the toughest
place to see anything is directly in front.
Copyright © Tracie Hotchner – Originally appeared in The Dog Bible: Everything Your Dog Wants You to Know by Tracie Hotchner
