About The Dog’s Sight

陳小敏

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.

狗特別擅長感知運動。西普尼夫斯基說：“狗的視網(wǎng)膜中視桿細胞數(shù)量多，這使得它們觀察運動的能力更強?！边@種能力可以幫助它們發(fā)現(xiàn)像松鼠等小獵物。

狗的視野比人類更廣。狗比人的眼間距稍遠，因此它們可以在每個方向上看得更遠。

狗的遠距離視力比人類更模糊。擁有完美視力的人類有20/20的視力，而狗有20/65至20/85的視力。這意味著“狗必須在20英尺（約合6米）處才能看見一個擁有20/20視力的人類在65或85英尺處能看到的字”。

狗很難近距離觀察事物。“當物體距離眼睛至少13到20英寸（約0.3到0.5米）遠時，狗狗能看清楚，”但如果物體更近，眼中的圖像可能就會模糊不清。人類可以看到更近的物體，大約到10 英寸（0.25米）遠。

狗可以通過身形和動作識人。內(nèi)茨說：“如果你的狗能從遠處認出你，那不是因為它能像人類一樣看清楚你的臉，而是因為認出你的身形或移動方式?！?/p>