Blinking is an involuntary rapid eye-closing action and is a normal physiological phenomenon. People blink without realizing it. It is estimated that the average person blinks more than ten times per minute, usually blinking once every 2-6 seconds, with each blink taking 0.3-0.4 seconds. The cornea of the eye is transparent like glass, and there are no blood vessels in it to ensure that light can pass through well. The cornea is supplied with nutrients and moisture by a liquid called aqueous humor in the eye, as well as tears secreted by the lacrimal gland. Because the cornea and sclera on the front surface of the human eye are exposed to the air for a long time, the moisture on them evaporates easily and becomes dry. Blinking allows tears to be evenly applied to the front surface of the eye, making the cornea and conjunctiva less prone to dryness, maintaining the smoothness of the corneal surface, and promptly removing dust and bacteria on it. In addition, blinking can temporarily block external light from entering the eye, allowing the retina and the muscles of the moving eye to rest temporarily. Therefore, blinking is actually a protective action. Especially for people who stare at computer or TV screens for a long time, blinking more often can avoid dry eyes and visual fatigue.
Blinking is also a kind of neural reflex activity. When the eyes are stimulated, such as when dust suddenly blows into the eyes, when objects like flying insects suddenly fly towards the eyes, or when strong light shines into the eyes, people will quickly close their eyes. If the eyes do not close when exposed to strong light, it usually indicates that there is a problem in a certain area of the brain. Conversely, people with eye diseases such as chronic conjunctivitis, trachoma, and superficial punctate keratitis who blink excessively due to eye discomfort are also abnormal.
In addition, blinking is a way of emotional communication between people. This often occurs between people who are relatively close, which can be a tacit understanding between two people, or a hint, replacing words to let the other person understand what they are thinking and hoping for their cooperation. Some children, imitating others' blinking movements, develop the habit of frequent blinking, which can be annoying. This is a bad habit and should be corrected.