About The Dog’s Sight

陈小敏

Dogs are especially good at sensing movement.“Theincreased number of rods in the dog’s retina also increasestheir ability to detect motion，”Sypniewski says. This abilitycan help them detect small prey like squirrels.

Dogs have a wider field of vision than humans. Dogs’eyes are set slightly farther apart than humans’eyes， sothey can see further to the side in each direction.

Dogs have blurrier long- distance vision than humans.A human with perfect vision has 20/20 vision， while dogshave 20/65 to 20/85. This means that“a dog must be at 20ft. to read a letter that a human with 20/20 vision would beable to read at 65 or 85 ft.，”says Sypniewski.

Dogs have trouble seeing things very close up. Dogscan see objects clearly if they’re at least 13 to 20 inchesaway from their eyes，“but if the object is closer， the imagemay be blurry，”Sypniewski says. Humans can see objectsslightly closer — about 10 inches away from the eye.

Dogs may recognize you by your shape and motion.“If your dog recognizes you from a distance， it is not becauseit can see the details of your face like a human would，but rather because of your shape or the way you move，”Neitz says.

狗特別擅长感知运动。西普尼夫斯基说：“狗的视网膜中视杆细胞数量多，这使得它们观察运动的能力更强。”这种能力可以帮助它们发现像松鼠等小猎物。

狗的视野比人类更广。狗比人的眼间距稍远，因此它们可以在每个方向上看得更远。

狗的远距离视力比人类更模糊。拥有完美视力的人类有20/20的视力，而狗有20/65至20/85的视力。这意味着“狗必须在20英尺（约合6米）处才能看见一个拥有20/20视力的人类在65或85英尺处能看到的字”。

狗很难近距离观察事物。“当物体距离眼睛至少13到20英寸（约0.3到0.5米）远时，狗狗能看清楚，”但如果物体更近，眼中的图像可能就会模糊不清。人类可以看到更近的物体，大约到10 英寸（0.25米）远。

狗可以通过身形和动作识人。内茨说：“如果你的狗能从远处认出你，那不是因为它能像人类一样看清楚你的脸，而是因为认出你的身形或移动方式。”