A Huge Discovery  一个重大的发现

因为这些原因，那时世界上只有不到500人佩戴了这种隐形眼镜，其中包括了Efron。此外在高空运作的情况下，佩戴了隐形眼镜的眼球最长只能忍受4小时。直到1948年，美国视光师凯文·托赫（Kevin Tuohy）偶然中发现镜片其实不必覆盖整个眼白，这样的话镜片的穿戴时间又能额外延长几个小时。随后托赫抛弃了原来的玻璃镜片，转而使用一种透明的塑料，并且他将镜片的边缘抛光，这使得镜片更加瘦小。令他惊奇的是，这种改良的镜片即使是在眨眼之后也能保留在原来的位置。

For these reasons, very few people—maybe 500 in the world, estimates Efron—wore early models. It wasn't until 1948, when optical technician Kevin Tuohy realized by accident that contacts didn't have to cover the whites of the eyes at all, that wearers were allowed some extra hours. While Tuohy was lathing the lens, a recently invented transparent plastic, the part supposed to cover the whites of the eyes dropped off. This left him thinking, Is there a way the smaller lens could actually work? So he polished down the disk's edges and tried the slimmer model himself. To his surprise, it actually stayed put—even after blinking.

The discovery was huge. "It changed the whole history of contact lenses," says Efron. But it was not without problems. First iterations were abrasive to the sensitive cornea, which was obviously not good. The new shape also had a bit of a lift at the edge, which meant lenses popped out at every available opportunity.

以上图片摘自torontocontactlenses。