Blink
Blink
Blink (/blɪŋk/), from the Old English blincan meaning "to move suddenly", is a rapid closing and opening of the eyelid. It is an essential function of the human eye that helps keep the eyes clean and moist by spreading tears across the surface.
Function
The primary function of a blink is to cleanse and moisturize the eye by spreading tears over its outer surface. It also serves to protect the eye from irritants such as dust and other small particles.
Blinking is controlled by the orbicularis oculi muscle, which is responsible for closing the eyelid, and the levator palpebrae superioris muscle, which opens it. The act of blinking is regulated by the central nervous system and can be both a voluntary and involuntary action.
Frequency
The frequency of blinking varies depending on a number of factors, including environmental conditions, activities, and individual characteristics. On average, a person blinks approximately 15-20 times per minute. This rate may increase in response to stimuli such as wind, bright light, or eye irritation.
Related Terms
- Blink reflex: An involuntary blinking response to a stimulus such as a sudden light or threat to the eye.
- Blepharospasm: An abnormal, involuntary blinking or spasm of the eyelids.
- Dry eye syndrome: A condition that occurs when the eyes do not produce enough tears, often leading to increased blinking.
See Also
External links
- Medical encyclopedia article on Blink
- Wikipedia's article - Blink
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