Why Do We Blink?

Have you ever been in the middle of a staring contest and you feel like your eyeballs are going to burn out of your skull because you just NEED to blink? Your friend might have blinked first, but you eventually followed suit because not blinking just isn’t an option. The current world record for a staring competition lasted 40 minutes and 59 seconds (we do NOT recommend—there’s a reason that the winner is called Fergal “Eyesore” Fleming). 

The average person blinks somewhere between 15-20 times per minute and it takes about 400 milliseconds to blink. Although there is no specific number for how often a person should blink, frequent blinking is necessary to clear away particles and lubricate the eyeballs. Blinking also helps prevent infection and clears your eye so you can have sharper, brighter vision. If you wear contacts, frequent blinking is even more important because it actually replenishes the tear layer that the contact lens floats on! Unfortunately, patients who wear contacts tend to blink less and have a higher number of incomplete blinks (meaning a lack of lid-to-lid contact). This reduced blinking leads to higher rates of red anddry eyes. 

The Mechanics Of Blinking

When it comes to the mechanics of blinking, we can separate blinks into several different types. Involuntary blinks are spontaneous and subconscious, and account for the majority of your blinks over the course of the day. These blinks serve to lubricate the eye by releasing a tear film (water, oil, and mucus) that acts to keep the eyeball smooth and wet. These also help “blink out” any foreign body in the eye, such as an eyelash or dust particles. In addition to hydrating the eye, the tear film also supplies oxygen to the eye and contains enzymes that fight bacteria and prevent eye infections. When you cry, you blink more often to prevent tears from building up on the eye, which would cause blurry vision. When you don’t allow yourself to blink, your eyeball begins to dry out, which can actually feel like a scratch on your cornea. Ouch!

Reflex blinks happen in response to something external, such as a bright light, loud noise, or when something unexpectedly pokes you in the eye. Voluntary blinks are blinks you do on purpose—for example, digital eye strain or driving for extended periods of time can leave your eyes feeling dry and tired, so blinking your eyes a few times can help alleviate discomfort. Voluntary blinks can also include blinking exercises to relieve eye strain. 

Although it looks like only the top lid moves when you blink, the process of blinking actually moves both the upper and lower lid together. The top lid does the biggest movement (opening and closing), but the lower lid does move upwards the slightest bit. A full blink brings tears from the tear gland and sweeps them across the eye like a windshield wiper. A full blink is necessary for the meibomian glands to release meibum. These are glands that line the edges of the eyelids and secrete oil that coats the eye’s surface and keeps the water component of our tears from drying out. 

Blinking Problems

There are many different reasons you might need to blink more than normal. If you have an  ingrown eyelash, for example, you may blink more frequently. Allergies, pink eye, stress, anxiety, tics, and undiagnosed refractive errors can also cause excessive blinking. A thorough eye exam will typically be able to determine the cause. 

Blinking more slowly or less often happens as well, particularly if there is damage to the facial nerve that is responsible for closing the eyelid. Slow or infrequent blinking can also be caused by certain medications or if you’re hyper-focused on something (like a screen). This is why it’s particularly important to remember to frequently blink your eyes when you’re using devices so you don’t experience dry eye or eye fatigue. Research shows that we blink 66% less while using a computer. To combat resulting dry eye/fatigue, try the 20-20-20 rule—every 20 minutes, look away from your computer and rest your eyes on something 20 feet away for 20 seconds. Reminds yourself to blink while looking at your screen, and use eye drops if necessary!

Blinking And The Brain

Blinking does more than just clear your eyes! According to studies, people also blink to give the brain a rest! On average, humans spend about 10% of their waking hours with our eyes closed, thanks to blinking. This means that for 10% of the day, you are receiving zero visual input. How do we not notice? Our brain suppresses the nerve signal that tells us that the picture has changed so that the flow of visual information seems uninterrupted. According to scientists, briefly closing our eyes helps us gather our thoughts and focus attention on things around us. Interestingly, people tend to blink at the end of a sentence when reading rather than in the middle of a sentence. In other words, we subconsciously blink as a “resting point” for our brain. 

What Happens When We Don’t Blink?

When you stop blinking, your cornea experiences a lack of oxygen from the tear film and begins to swell. Your eyes start to dry out, resulting in eye pain and blurry vision. Your risk of eye infections is suddenly much higher, thanks to a lack of oxygen and nutrients to the eye and an inability to flush out debris. Eventually, tiny particles would scratch the surface of your cornea and your eyesight would lose sharpness. The result? Irreversible damage to your vision and a tremendous amount of discomfort! Fergal “Eyesore” Fleming lasted 40 minutes without blinking, and compared the sensation to getting a tattoo on your eyeballs. No thanks!