Collectors rely on their eyes for so much. But those who closely examine coins have other sets of eyes too. How many visual aids do you use, besides maybe a pair of glasses or contacts?
Many serious collectors own a magnifier or a loupe, or both. A simple magnifier enables you to see all details of a coin, the wear patterns, the Mint luster. Specialists in early coins, such as large cents, can rely on a loupe for close work, to discern the many different varieties. Collectors who enjoy searching for error coins use such aids that help in identifying special coins, and can even lead to the discovery of a new variety.
I once knew a coin authenticator who used a microscope in his work. Detailed work to be sure.
How many numismatists are also interested in astronomy? Over the years, I've met a great number of coin lovers who enjoy looking at the stars and planets, who observe eclipses and other phenomena. Amateur astronomers can own a telescope, or at least a pair of binoculars, to spot details on the moon, to see the clouds of Jupiter and the rings of Saturn. More optical aids!
Perhaps coin enthusiasts are a special breed for whom a pair of eyes is not enough. Think of all the ways you use lenses, looking at coins, pursuing another hobby. From looking at tiny half dimes to studying the largest planet, optical aids are a valuable and essential part of a numismatists' life.