EYELASHES, as any would-be femme fatale knows well, are seductive. But that is probably not their main purpose. Men rarely flirt by fluttering their eyelids, yet men have eyelashes, too. Moreover, the market for false lashes suggests that if seduction is their principal job, they are not as good at it as they could be.
Surprisingly, the real reason eyelashes evolved has remained unknown. Research shows that those who lack lashes, which some people do, suffer higher than average rates of eye infection. That suggests they have some sort of protective function. But exactly what this is and how it works has been a mystery. Some people hypothesise that lashes protect eyes from falling dust. Others think that they act rather like an animal's whiskers—detecting foreign bodies before they can do harm, and triggering a protective blink.
David Hu of the Georgia Institute of Technology and his colleagues think they have cracked the problem. Eyelashes do not protect eyes directly, they believe. Rather, they change the flow of air around the eye in ways that stop dust and other irritants getting in, and moisture getting out.
...
from The Economist: Science and technology http://ift.tt/1LENGw1
No comments:
Post a Comment