Out of all the twitches a person can get, an eyelid twitch is probably the most annoying.  Not only is its presence constantly noticed, but very rarely can other people notice it, robbing the patient of the validation that yes it is twitching, and no they aren't going insane.  That being said, the vast majority of eyelid twitches are completely benign and will resolve on their own (important caveat: if the twitch involves a facial muscle, or an actual involuntary forced blink, then the condition needs to be seen by your doctor).

The proper term for the twitch is eyelid myokymia, and involves the sporadic firing of a neuron in the upper or lower eyelid, causing a sporadic muscle contraction.  The cause of this sporadic firing is not entirely known, although there is a link with increased levels of stress, lack of sleep, and/or increased consumption of caffeine (i.e a typical workday).  Reducing or removing any of these stressors is the most effective way stop the eyelid from twitching, although it is not unheard of for some to last weeks or even months.  From practical experience, simply educating a patient that the twitch is completely benign and harmless is frequently all that is needed to break the psychological self-reinforcing feedback loop that may be fueling the twitch in the first place (eyelid twitches ---> patient gets stressed that it might be problem ---> eyelid twitches again ---> patient more stressed that it might be a problem... and so on).

Some patients, however, want a quicker fix, something more proactive than simply cutting back on coffee.  A quick google search will show various sites espousing the benefits of another treatment option, the consumption of tonic water.  The science behind this idea is that tonic water has historically contained a compound called quinine (which gives tonic water that coveted slightly bitter taste),  which seems to have a muscle relaxing property.  Quinine has previously been used for the treatment of another involuntary muscle spasm, restless leg syndrome, so it's not a stretch to see why it may be effective in stopping eyelid twitches.  However, the effective dose and the toxic dose of quinine are quite similar, which therefore makes it a fairly dangerous medication, as taking slightly too much can cross the line from helpful to hurtful.  In fact, the FDA has warned against the use of quinine for the treatment of leg cramps, and has banned over-the-counter medications containing quinine as a muscle relaxant.  That being said, there is still a very small amount of quinine in tonic water, so desperate eyelid twitch sufferers can safely try drinking a glass or two of it (but not ten), and it won't be harmful (and therefore probably not effective either).

As an aside, the history of quinine is fairly interesting, originally being harvested from tree bark in Peru in the 17th century and used to stop the shivering of people with fevers.  A priest in the area sent some back to Europe to help with calming the shivering seen in people inflicted with malaria, since there was a malaria epidemic in Rome at the time which had claimed the lives of several popes and cardinals.  Miraculously, and by sheer luck, not only did the shivering stop, but the malaria was cured in patients who consumed the quinine.   For the following few centuries, up until about 1920 it was the main treatment and prophylaxis to malaria, until safer medications became available.  There is some evidence that the gin and tonic was invented by the British colonist in India as a twist on their antimalarial routine, so they could "enjoy" their malaria prophylaxis at cocktail hour instead of drinking their medicine at dawn.  And there likely was very few eyelid twitches in that bunch.

Dr. Burke is an optometrist practicing at Calgary Vision Centre.  Opinions above do not constitute medical advice, and readers should consult with their optometrist if they have questions or concerns about their eye health