vision、eyesight、sight与perception这些名词均含“视力、视觉”之意。
vision : 书面用词，含义广泛，指人的视力或视野，也可指远见卓识。
- The couple moved outside her field of vision.
这对夫妇离开了她的视野。 - He glimpsed something on the edge of his vision.
他斜眼瞥见了点什么。
eyesight : 普通用词，指眼睛的正常功能。
- You need to have your eyesight tested.
你得去查查视力。Want to learn more?
sight : 普通用词，与eyesight同义，可换用，指由实实在在的事物引起的视觉。
- If your sight is poor, you should not drive a car.
视力不佳就不应该开车。 - The old woman has lost her sight (= has become blind).
那位老妇人失明了。
perception : 指视觉，也可泛指其它器官的功能，或引申指敏锐的理解力。
- She has extraordinary powers of perception for one so young.
她年纪轻轻就有着非凡的洞察力。 - He's not known for his perception.
他的洞察力并不怎么样。
