如果说年轻时近视的我们，老了之后会远视，那么，是不是会有那么一段时间，我们的视力能好到看清视力表最下面那一排“鬼画符”呢？

答案是：不一定。

事实是这样的：

Babies are actually farsighted, and as they grow older their eyes grow too until they reach a point of "perfect" eyesight, called emmetropia.

刚出生的婴儿都是远视眼，但随着年龄增长，眼睛也会发育，直到“视力正常”，学术上叫做“屈光正常”（emmetropia）。

出生的时候，婴儿都一样，都是远视眼。等慢慢长大，儿童的视力就正常了。但很多人青春期长着长着就过了那个点，变成了近视。

It isn't entirely worked out what cues the eye that it is time to stop growing, but we know that in many kids the eye continues to grow past emmetropia and they become nearsighted.

其实直到现在（科学家）也还没有完全弄清楚是什么因素“告诉”眼睛该停止发育了。但我们知道，很多孩子的眼睛在视力正常后继续发育，结果变成了近视。

Basically, when the eye grows too long the light inside the eye comes to a focus in front of the retina rather than at the retina, causing blurry vision, so we must wear glasses to change the optics and focus the light onto the retina again.

是这样的，如果眼睛的前后距离太长，眼睛里的光线就会聚焦在视网膜前面而不是视网膜上，从而造成了模糊的视觉，因此，我们必须戴上眼镜来改变光线的路径，使它再次聚焦到视网膜上。

When we age, we suffer a different process. Our tissues become stiffer and the lens doesn't adjust as easily so we start to lose near vision as well.

随着年龄增长，我们会经历一个不同的过程。我们的眼部组织会变得僵硬，晶状体的活动性也变差，渐渐地，我们就连近的东西也看不清了。