Wearing a facial covering or mask—as many of us are doing this summer—draws a lot of attention to your eyes! Because of masks, you’re likely noticing other peoples’ eyes and eyebrows more than ever. Have you ever wondered why humans evolved to have eyelashes and eyebrows, and what functions these perform in overall eye health and function?

In addition to being uniquely expressive, eyebrows and eyelashes serve as the first line of natural defense against airborne debris and other hazards getting into the eyes.

How do eyelashes protect your eyes?

The focus on eyelashes is often for their aesthetic beauty. And indeed, mascara, eye makeup and false eyelash sales are increasing during the Covid era. However, while they add drama to the eyes, eyelashes also serve a critical function in eye safety.

Have you ever gotten a piece of lint or a grain of sand caught in your eyelashes? That’s the preventive nature of eyelashes in action. Eyelashes are a first line of defense for your eyes, keeping airborne dirt, dust, lint and other debris from reaching the delicate eye tissues.

With eyes open, eyelashes catch some airborne debris, but when closed, eyelashes form a nearly impenetrable barrier against foreign irritants in the eye.

Eyelashes are also incredibly sensitive.

How sensitive? Reach up and touch the very tip of one of your eyelashes. No matter how lightly you touch them, you can sense it immediately. Touching your eyelashes also triggers your body’s blinking reflex, which occurs to prevent debris or dirt from getting any closer to the eye itself. The blinking reflex is why it can be challenging to keep your eyes wide open while inserting a contact lens or applying makeup.

And while we mentioned false eyelashes above, we don’t recommend wearing them. The glue necessary to attach them to your eyelids can be an eye irritant. Extra “added” lashes can also be detrimental to the natural function of eyelashes, increasing your risk of dust exposure and even dry eye. Anytime you put a foreign material—mascara, false lashes, other cosmetics—near the eye, you risk eye infection and allergic reactions. If you must use these, do so very sparingly and practice the highest level of good hygiene with cosmetics and other eye accoutrements.

Why do we have eyebrows?

With everything the eyelashes do to protect the surface of your eyes, what purpose do eyebrows serve in eye health?

Though they’re positioned farther away from delicate eye tissue, eyebrows serve an essential purpose. The next time you’re outside in the hot summer sun and sweat starts dripping down your forehead, notice what happens. The eyebrows are positioned along the brow bone to help channel sweat and other liquids away from your eyes. Thanks to eyebrows, sweat flows down the side of your face so it won’t go directly into the eye socket.

Whether it’s sweat, rain, or shower water, eyebrows do a great job of re-routing liquids away from the eyes. Both the shape of your eyebrows and each individual hair within the brow play a role in this function.

Just as wearing false eyelashes can interfere with the natural protective function eyelashes serve, removing too many individual eyebrow hairs in the name of cosmetic appeal can hinder functionality. Your eyebrows evolved to serve their protective function, so don’t overpluck them.

The current trend of a “bold brow” is much healthier for your eyes than overplucked eyebrows—not to mention much less painful!—so we hope that trend is here to stay.

Why do we blink?

Blinking your eyes is necessary to maintain good eye health and lubrication. Did you know that the average adult blinks 10 to 20 times per minute? And that each blink takes just one-tenth of a second? What happens in that millisecond is critically important, though.

Blinking is a natural function that cleans and refreshes your eyes. When you blink, a thin layer of natural tear film spreads across the cornea of your eye. That tear layer keeps the eye moist while whisking away particles of dust or dirt that could irritate the eye and interfere with good vision. The excess tears and any particles of debris are washed down through your tear ducts into the nasal passages. This connection is also why you probably get a runny nose when you cry – the tear film and nose are interconnected.

Though the blinking rate is typically 10 to 20 times per minute, some tasks can be so intense that they interfere with your natural tendency to blink. Blinking less than usual isn’t ideal, because it reduces the frequency of that cleansing, refreshing bodily function. If you’re staring intently at a screen or reading a book, studies show that you may blink a lot less—sometimes as few as 3 to 8 times each minute. That’s a significant drop from the normal, healthy blinking rate. Over time, less frequent blinking can lead to conditions such as dry eye and eye strain.

Be intentional about blinking

Though blinking is involuntary, it’s a best practice to think about it and remember to blink more often during high-intensity visual activities. When staring at a screen and working hard on a project, remember to close your eyes occasionally, on purpose. This rest will be a welcome and healthy moment for your eyes!

If you can’t remember to blink while you’re highly focused, set a phone reminder each hour and purposefully close your eyes. Close them completely, pause, then squeeze your eyelids together intentionally so you can feel the top and bottom eyelids touching. Then pause again with your eyes closed for several seconds. Finally, open your eyes again and enjoy a more relaxed, refreshed feeling.

If your eyes feel tired or dry after hours spent staring at a screen, make an appointment to see us about getting a pair of computer glasses to ease eye strain, or for a dry eye disease screening.

The eyes are one of your body’s most important organs. When you take good care of them and support their natural function, they can perform their best. We’re here to help you take excellent care of them for a lifetime of healthy vision.