英語(yǔ)聽(tīng)力文摘 隱形眼鏡的秘密

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為什么戴隱形眼鏡看東西更清楚?

Don:I get contact lenses to replace my glasses and it’s like I’m seeing the world through new eyes. It’s miraculous!

Yaël: Acutlly, Don, there is nothing miraculous about it.

D: Who tell?

Y: Well, like glasses, contact lenses work by bending light rays just the right amount to make the object come into focus on the retina at the back of the eye. Sometimes the eye’s natural lens has an imperfection or may not be shaped properly, which can make your vision blurry or distorted. Depending on your vision, the right kind of lens helps your eye focus light properly and project a clear image onto the retina.

D: Ok, fine. But why do contact lenses make things seem so clear?

Y: Patience, younger princess! Glasses have what’s called an optical center, which means that objects appear clearest when viewed through the center of the lenses. But when you’re wearing glasses and you move your eyes to the side, or up, or down, things can seem slightly distorted or blurry.

D: So because contacts are right on the eye and move with the eye, there’s no optical center.

Y: Right! To put it another way, the entire contact lens is the optical center. So no matter which way you move your eyes, objects appear in perfect focus.

Don:終于擺脫框架眼鏡了，從隱形眼鏡看世界，感覺(jué)是全新的!真是太神奇了!

Yaël:Don,事實(shí)上，這是你的錯(cuò)覺(jué)。

D:你怎么知道?

Y:和框架眼鏡原理一樣，隱形眼鏡調(diào)節(jié)適量的光線進(jìn)入眼睛，在眼睛后的視網(wǎng)膜上聚焦成像。有時(shí)候，眼睛晶狀體老化或不完善都將造成視力模糊或扭曲。適合你視力的隱形眼鏡糾正視力，輔助眼睛屈光，在視網(wǎng)膜上清楚成像。

D:好吧，那么你能說(shuō)說(shuō)為什么戴隱形眼鏡看東西更清楚嗎?

Y:別急呀，老兄!框架眼鏡的鏡片上有光心，當(dāng)視野正好穿過(guò)，看到的圖像最清楚。但是，當(dāng)你戴框架眼鏡，上下左右轉(zhuǎn)動(dòng)眼珠，看到的東西就略顯模糊或扭曲。

D:所以，因?yàn)殡[形眼鏡直接接觸眼珠，跟隨眼珠轉(zhuǎn)動(dòng)，就不存在光心了。

Y:就是這樣，或者你把整個(gè)隱形眼鏡都看作光心，無(wú)論你怎么轉(zhuǎn)動(dòng)眼珠，視野正好透過(guò)光心。