Eye blinking
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Clinic
- Semi-autonomic rapid closing of the eyelid.
- 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.
- It is an essential function of the eye that helps spread tears across and remove irritants from the surface of the cornea and conjunctiva.
Three types
- Spontaneous blink: Spontaneous blinking is done without external stimuli and internal effort. This type of blinking is conducted in the pre-motor brain stem and happens without conscious effort, like breathing and digestion.
- Reflex blink: A reflex blink occurs in response to an external stimulus, such as contact with the cornea or objects that appear rapidly in front of the eye. A reflex blink is not necessarily a conscious blink either; however it does happen faster than a spontaneous blink. Reflex blink may occur in response to tactile stimuli (e.g., corneal, eyelash, skin of eyelid, contact with eyebrow), optical stimuli (e.g. dazzle reflex, or menace reflex) or auditory stimuli (e.g., menace reflex).
- Voluntary blink: A voluntary blink is a conscious blink, with the use of all 3 divisions of the orbicularis oculi muscle.