Why Do We Have Eyelashes and Eyebrows?
Eyebrows and eyelashes keep dust from getting into our eyes. Eyelashes are sensitive to touch. They make the eyelid close automatically when a foreign object suddenly moves near the eye. Your eyebrows stop the sweat that forms on your forehead when you are hot from running into your eyes.
The covering of hair also shields the brow, or ridge, above the eyes from bumps. Eyebrows and eyelashes also serve the visual function of calling attention to the eyes, just as we call attention to an important word in a letter by underlining it.
Eyelashes also help to keep moisture, like sweat or rain, out of your eyes. Their curved shape and the way they are positioned allow them to direct moisture away from your eyes.
Along with your eyebrows and forehead, your eyelashes also help to shield your eyes from the bright light of the sun. They’re not a substitute for sunglasses, but they do help to filter the sunlight that shines in your eyes.
Eyelashes are hair, so they’ll fall out naturally from time to time. Like the hair on your head, they grow back on their own, too. When an eyelash falls out, it can take a month to six weeks to grow back.