A group of scientists at the Georgia Institute of Technology, led by David Hu, determined the primary purpose of eyelashes is to divert airflow around the eye. They’re not just elegant, feathery flirting-aides? They’re hardworking, highly employed air traffic controllers of the eyeball? It’s all entirely unexpected news.
Anyway, the research published in the Journal of the Royal Society Interface notes that eyelashes of most mammals are one third as long as the eye is wide, which is the most efficient length for diverting airflow around the eye and reducing evaporation. Dr. Hu and his team employed wind-tunnel experiments to verify.
Previously, theories proposed that eyelashes existed to collect dust from above (which sounds like a beautiful job), or lashes acted as sensors to encourage protective blinking (so brave), or they aided in seduction (why else would they be so fluttery). But, noted Dr. Hu, our preferred longer lashes are actually inefficient: Eyelashes that are too long direct air right into the eye. Beautiful people do have it hard.