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Spasm means "uncontrolled muscle contraction". The term blepharospasm ['blef-a-ro-spaz-m] can be applied to any abnormal blinking or eyelid tic or twitch resulting from any cause, ranging from dry eyes to Tourette's syndrome to tardive dyskinesia. The blepharospasm referred to here is officially called benign essential blepharospasm (BEB) to ...
Blepharospasm is often associated with dry eyes, but the causal mechanism is still not clear. [16] [8] Research in New York and Italy suggests that increased blinking (which may be triggered by dry eyes) leads to blepharospasm. [24] [25] A case control study in China found that blepharospasm aggravated dry eyes. [26]
Blinking is a bodily function; it is a semi-autonomic rapid closing of the eyelid. [1] A single blink is determined by the forceful closing of the eyelid or inactivation of the levator palpebrae superioris and the activation of the palpebral portion of the orbicularis oculi, not the full open and close.
In children, the most common cause is a stroke of the ventral pons. [9]Unlike persistent vegetative state, in which the upper portions of the brain are damaged and the lower portions are spared, locked-in syndrome is essentially the opposite, caused by damage to specific portions of the lower brain and brainstem, with no damage to the upper brain.
Evidence has shown that newborns' eyes do not work in the same fashion as older children or adults – mainly due to poor coordination of the eyes. Newborn's eyes move in the same direction only about half of the time. [17] The strength of eye muscle control is positively correlated to achieve depth perception.
Nowhere near as often as we do. Humans tend to blink between 15-20 times a minute, and as we've already mentioned, it's an essential thing we do automatically to keep our eyes in good condition.
The corneal reflex, also known as the blink reflex or eyelid reflex, [1] is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), though it could result from any peripheral stimulus. Stimulation should elicit both a direct and consensual response (response of the opposite eye).
Bell's phenomenon (also known as the palpebral oculogyric reflex [1]) is a medical sign that allows observers to notice an upward and outward movement of the eye, when an attempt is made to close the eyes. The upward movement of the eye is present in the majority of the population, and is a defensive mechanism. [2]