Why, when I am tired, does my eyelid sometimes flutter?
• The involuntary muscle contractions that ripple across an eyelid are called . They appear spontaneously and usually disappear again within a few days, though they can persist for up to three weeks. They are triggered by stress, fatigue or eyestrain, and can be exacerbated by caffeine or alcohol.
Readers familiar with the series of Looney Tunes of a may recall that the earliest cartoons apparently showed Wile E. Coyote’s facial muscles twitching to convey the stress of being outwitted yet again. The animators were taking poetic licence because, though people with myokymia are acutely aware of the twitching and might even see the fluttering motion in their peripheral vision, it is virtually imperceptible to an observer, as can be confirmed by looking closely at the offending eyelid in the mirror.
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“Although people are aware of their eyelids twitching, it is virtually imperceptible to an observer”
Myokymia is quite different to the erratic blinking that may be a sign of anxiety, particularly in young people. This anxiety can also be manifested as shoulder shrugging and mouth twitching. Sometime between their 7th and 14th birthdays, about 1 in 3 boys and 1 in 10 girls will experience this anxiety and its symptoms.
Intense, longer-lasting and more widespread shaking of the body might indicate caffeine poisoning, alcohol withdrawal, an overactive thyroid gland or Parkinson’s disease.
Mike Follows, Willenhall, West Midlands, UK