Why Do We Blink? What Does It Do to Our Eyes and at What Frequency Is Considered Normal?

In some situations, a person must keep their eyes open for long periods. This can be difficult for most people because of our instinct to blink. But why do we need to blink?

(Photo: Pexels/ Tran Long)

What Does Blinking Do to Our Eyes?

According to ophthalmologist Dr. Brenda Pagan-Duran from the American Academy of Ophthalmology, humans blink for two main reasons. First, blinking helps clear away particles from the eyes. A foreign object must be removed immediately if it finds its way under the eyelid or gets blown in.

Second, blinking lubricates a person's eyeballs. Our eyes need a smooth surface so light can pass through properly without having blurry vision. When a person blinks, a tear film composed of mucus, oil, and water is released to keep the surface of the eyeball smooth. This film also provides a pathway for white blood cells in the presence of injury to the eye's surface.

Blinking also prevents the eye from drying out, which can be comfortable. A large area of dryness almost feels like a scratch on the cornea, and it can be very painful because of many nerve endings in this layer.

Aside from this, the blinking also helps supply oxygen to the eye. Since blood vessels do not reach the cornea, oxygen is directly transferred to it by the tear film. It also contains enzymes that fight bacteria and prevent eye infections.

Blinking is also a common action during emotional times. When people cry, they flicker more often to clear away the tears. Doing so prevents the tears from building a lake on the eye, which could blur vision.

Studies also suggest that humans blink for their brains. Experts speculate that blinks allow the body to get a brief mental rest without visual stimuli. It was also found that when people flashed, mental activities increased in some areas of the brain, functioning when the mind is in a wakeful rest. They believe activating this brain area is a short mental break that enables better attention when the eyes open again.

How Frequent is Normal Blinking?

Blinking is a reflex action. It usually happens involuntarily, but a person can make themselves blink. Most people blink between 10 to 20 times per minute. This means that while awake, people probably blink 14,400 to 19,200 times a day.

Each blink lasts between 0.1 to 0.4 seconds, making up about 10% of the time a person is awake. However, there are instances where an individual might blink more or less often.

A common reason a person may blink less often is due to computer vision syndrome. This can happen when someone uses a computer for a long time without a break. Eyelid problems such as injury and paralysis can also cause a person to blink less often.

On the other hand, blinking more frequently can be annoying, but it is rarely a sign of a serious concern. In rare cases, frequent blinking could be a sign of a more severe condition such as multiple sclerosis, Tourette syndrome, Wilson's disease, and seizure disorders.