Ever had an eye twitch? If you have, you will know exactly how annoying they are. That persistent quiver of your lower lid you think must be glaringly obvious to everyone around you, when in reality they can't see a thing.
(This, perversely, may be one of the most annoying things about them.)
So what exactly is an eye twitch and how can you MAKE IT STOP?
First of all -- don't stress. According to ophthalmologist Dr Bill Glasson, eye twitches are quite common, even if they are irritating.
"It's called a orbicularis myokymia, which is a vibrating or twitching of the eyelid," Glasson told The Huffington Post Australia.
"It can be quite off-putting for the patient because it can feel quite pronounced, and you might be thinking, 'everyone must be noticing it, I can feel it jumping around'.
"But in actual fact, no one can see it."
Glasson stresses the twitch occurs in the eyelid and not the eye (in fact, this is where the term 'orbicularis' comes from -- it is referring to the orbicularis oculi -- which is essentially part of your eyelid) and the major trigger for the spasms is... wait for it... stress.
"I used to get it when I was studying hard for exams," Glasson said. "It is very common with people under stress.
"When someone comes to me with that kind of fasciculation [twitching], the first thing I say is, 'What you need is a holiday. You are going too hard. Take yourself for a break and it will disappear'."
Really? It's that simple? And is it really just stress that causes it?
"Most commonly it's associated with stress and tiredness, though you could argue there might be other causes as well," Glasson said.
"Sometimes it can be the result of some kind of thyroid disorder. You could argue a dry eye could cause it as well.
"Of course I'm not talking about if your whole face twitches -- that is completely different and in that case, you should seek the advice of a medical professional. But if we are talking locally, I would say 99.9 percent of the time it's not associated with anything neurological."
So, the bad news is your eye is twitching and you're stressed and over-tired. The good news? It's time to go on a holiday -- doctor's orders.
"What it really means is you need to slow down a bit," Glasson said.
"You need more sleep -- and I mean decent sleep -- and more relaxation and exercise. If you have the time, go for a holiday. That should clear it up right away."