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生活中我们常能看到这样的现象:一部分患近视的中老年人在观看远处物体(简称视远)时需要戴上近视镜,而在观看近处物体(简称视近)时又需要摘去近视镜,有的甚至还要换戴老花镜,或者配戴复合眼镜——镜片由两部分组成(上半部视远,下半部视近),而患近视的青年人一般就不会出现这种现象。这是为什么呢?让我们仔细研究一下这个问题。 1 近视矫正引起近点变远众所周知,近视眼是指远点(人眼看清物体的最远距离)变近的眼。正常眼的远点为∞,近视眼的远点s_1<∞。而近视矫正就是通过配戴发散透镜将人的远点从有限远“变”到无限远。由透镜成像公式
We often see this phenomenon in life: a part of the elderly suffering from myopia when viewing distant objects (referred to as farsightedness) need to wear myopia, and viewing objects in the vicinity (referred to as near) and need to pick To myopia, and some even need to wear reading glasses, or wearing glasses - the lens consists of two parts (as far as the first half, as the second half as near), and young people suffering from myopia generally do not This phenomenon occurs. Why is this? Let’s take a closer look at this issue. 1 correction of myopia caused by the more distant As we all know, myopia is far point (the human eye to see the farthest distance of the object) closer to the eye. The far point of the normal eye is ∞, the far point of myopia s_1 <∞. The correction of myopia is by wearing a divergent lens will be far from the limited distance “change ” to infinity. The lens imaging formula