Scientists have finally discovered the function of eyelashes
The previously mysterious hairs that surround mammals' eyes keep dust out and prevent evaporation, and they're the perfect length, scientists find
The mysterious function of eyelashes has been revealed at last - thanks to science.
After measuring the dimensions of nearly two dozen mammal eyes, performing a series of wind-tunnel experiments and engaging in some complex fluid dynamic modelling, researchers determined that most mammal eyelashes are one-third the length of their eyes - just the right length to minimise the flow of air over the eyeball.
This reduction of airflow was important because less moving air across the eye kept evaporation at bay and stopped irritating dust from getting deposited on the eye surface, the scientists reported in a study published in the Journal of the Royal Society Interface.
"All mammals have wet eyes, and airflow is the enemy of that," said Guillermo Amador, a doctoral student at the Georgia Institute of Technology, and the first author on the paper.
The comprehensive research into eyelash function began in 2012, after senior author David Hu's daughter was born with long, batting eyelashes, leading him to wonder about their function.
Hu, a mechanical engineer at the Georgia Institute of Technology, has been inspired by his young children before. The idea for a previously published study that found most mammals take 21 seconds to urinate, came to him while changing a nappy.