Blinking is a semi-autonomic rapid closing of the EYELID<\/a>. It is a vital function of the EYE<\/a> that helps spread TEARS<\/a> across the surface of the CORNEA<\/a> and remove irritants from the CONJUNCTIVA<\/a>. This action is essential for maintaining the TEAR FILM<\/a>, which provides moisture, oxygen, and nutrients to the outer layers of the eye while protecting it from debris.<\/p> The physiological process is controlled primarily by the ORBICULARIS OCULI MUSCLE<\/a>, which is innervated by the FACIAL NERVE<\/a>. According to research published by the National Center for Biotechnology Information<\/a>, the average human blinks approximately 15 to 20 times per minute. This frequency can vary significantly based on cognitive activity; for instance, the rate typically decreases during focused tasks, a phenomenon often associated with COMPUTER VISION SYNDROME<\/a>.<\/p> There are three main classifications of blinking: spontaneous, reflex, and voluntary. Spontaneous blinking occurs without external stimuli and is regulated by the BASAL GANGLIA<\/a>. Reflex blinking is an involuntary protective response to tactile, aural, or visual stimuli, most notably the CORNEAL REFLEX<\/a>. Voluntary blinking is a conscious action performed by the individual. Abnormalities in blink rate are sometimes used as clinical markers for neurological conditions such as PARKINSONS DISEASE<\/a> or TOURETTE SYNDROME<\/a>, as noted by the American Academy of Ophthalmology<\/a>.<\/p>