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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.
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).
The eyelids close or blink voluntarily and involuntarily to protect the eye from foreign bodies, and keep the surface of the cornea moist. The upper and lower human eyelids feature a set of eyelashes which grow in up to 6 rows along each eyelid margin, and serve to heighten the protection of the eye from dust and foreign debris, as well as from ...
Blepharospasm usually begins with occasional twitches of both eyelids, which progress over time to forceful and frequent spasms and contractions of the eyelids. In severe episodes, the patient cannot open their eyelids (apraxia), which severely limits their daily activities. Prolonged closure of the eyelids may result in functional blindness. [4]
It is, however, present behind forcibly closed eyelids in most healthy people and should not be regarded as a pathognomonic sign. Also, traumatic abrasions are generally located in the central or inferior cornea due to Bell's phenomenon. [citation needed] Bell's phenomenon does not occur during short blinks. [3] [4]
The nictitating membrane of a masked lapwing as it closes over the left eye, originating from the medial canthus. The nictitating membrane (from Latin nictare, to blink) is a transparent or translucent third eyelid present in some animals that can be drawn across the eye from the medial canthus to protect and moisten it while maintaining vision.
Rigid contact lenses can best be removed by pulling the eyelid tight and then blinking, whereupon the lens drops out. With one finger on the outer corner of the eyelids, or lateral canthus , the person stretches the eyelids towards the ear; the increased tension of the eyelid margins against the edge of lens allows the blink to break the ...
The menace response is one of three forms of blink reflex. It includes the reflexive blinking that occurs specifically in response to the rapid approach of an object. [ 1 ] The menace response comprises blinking of the eyelids , in order to protect the eyes from potential damage, but may also include turning of the head, neck, or even the trunk ...