The ideal eyelash length

Researchers in the US have revealed that an optimum lash length helps to protect the eye from dust and retain moisture

06 Mar 2015 by Ryan O'Hare

Eyelashes have a number of functions. They filter dust and dirt, act as fine touch sensors to warn when an object is too close to the eye, and can set hearts racing with a single flutter. But what is the ideal lash length?

According to new research, the optimum eyelash length is one third of the width of the eye.

Studying samples found in the American Museum of Natural History in New York, David Lu and colleagues from the Georgia Institute of Technology found that 22 species of mammal had the magic ratio of eyelash to eye length.

The group used a purpose built mini wind tunnel to test the aerodynamic properties of different models of lash lengths, finding that the lashes redirect the flow of air.

Shorter eyelashes did not stop the flow of air, creating a ‘stagnation zone’ above the eye’s surface. While longer lashes direct the flow of air to the ocular surface, increasing evaporation, and increasing the likelihood of the eye drying out.

The authors suggest that the optimum length minimises dust particles and evaporation of the eye surface. They suggest that “eyelash-inspired protection” could be used to protect optical sensors.

The research is published in the Journal of the Royal Society Interface.

Image credit: FlickrLickr


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