In the blink of an eye, eyelashes can grab attention and even spur on romance. As effective as it may be, flirting is not the primary purpose of lashes. Eyelashes have been hypothesized as sunshades, dust catchers, and blink-reflex triggers, says David Hu, a mechanical engineer at the Georgia Institute of Technology (Atlanta). He adds that until recently there’s been no systematic study of the true benefits of lashes. That all changed when researchers in Hu's lab compared eyelash length to eye size in 22 mammals in the American Museum of Natural History in New York. In the lab the tested various fake lash lengths and their effectiveness in preventing water from evaporating out of a petri dish (simulated eye surface). They discovered that lashes get longer as the eyes get bigger, and there is an ideal ratio that keeps the eyes optimally moist—lashes should be one-third the width of the eye.
This discovery is key for the beauty industry. Though long, luscious lashes are aesthetically appealing and popular among clients, super-sized lashes may do more harm than good to the eye. Lashes that are too long can funnel airflow into the eye causing more evaporation and dry eyes instead of the intended function as a speed bump to divert air away from the surface of the eye. This doesn’t spell the end of the extension trend, however encouraging clients to opt for added volume instead of length helps preserve the original function of lashes.
For more on the booming eyelash extension business, check out Eye Candy.