I'm not what I would call a "makeup person" — I don't wear anything on my face most days and when I do, it's a pretty lackadaisical effort. But I have always coveted ridiculously long eyelashes. So, I have always thought that false eyelashes are the singular fake thing that I might indulge in. Being lazy, working at home, and chronically short of cash, it's not something I have ever gotten around to. The semi-permanent fake eyelashes that last for several weeks cost upwards of $50, and the DIY version is time-consuming and seems difficult. 

But now I have a scientific basis for my fake-lash reticence. A new study by a group of scientists from Georgia Tech has found that the length of our eyelashes is actually very specific — lashes are about one-third the length of the width of our eyes. And that's not just for people. Across measurements from 22 different mammal species as different as armadillo, camels, rabbits, goats, kangaroos and leopards, that ratio holds up. 

And that ratio has a very important function — it protects eyes. According to the study, which involved using fluid dynamics models to study airflow (the researchers made a wind tunnel just for the experiment), lashes' natural length helps keeps moisture from evaporating from the eye, and simultaneously keeps dust out.

In the experiment, scientists tested wind speeds that approximated walking and running speeds for various animals. They found that too-short lashes can cause eye problems: "Short eyelashes create a stagnation zone above the ocular surface that thickens the boundary layer, causing shear stress to decrease with increasing eyelash length," the original study reports. In short, dust gets in, and too much moisture gets out when eyelashes are short. 

But too long is also problematic, in similar ways. 

"...if they get too long they start to channel more airflow towards the eye and that increases the evaporation and increases the deposition of the particles," fluid mechanics doctoral student at Georgia Tech Guillermo Amador, the lead author of the study told NPR.

Eyelashes are exactly the perfect length to protect eyes from debris and keep them wet enough. (Whether they curl or not has no bearing on their effectiveness, according to the researchers.)

"If women use false eyelashes they could actually dry out their eyes a little faster and have to blink more frequently," Amador told NPR.

So I'll be dropping those falsie dreams, since apparently, my lashes are perfect and so are yours. 

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Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.