Why is my eyelid twitching?
If you have ever had an eyelid twitch for an extended period of time, you know how annoying it is. An eyelid twitch (or tic) is when you have a spasm or slight movement of your upper or lower eyelid. It comes on suddenly, and can last for a minute, hours, days or even longer. 
Most common eyelid twitches are harmless, slight, and do not affect your vision. However, there are some neurological problems that can make eyelid muscles contract, such as blepharospasm and hemifacial spasm. These less common conditions generally tend to cause the eyelids to close more fully and for longer periods of time, limiting or completely blocking vision. Other muscles in the face may be affected as well.
For the majority of us, the common eyelid twitch is a brief and minor annoyance. But when it lasts longer or occurs more frequently than usual, there are some steps you can take to make it go away:
Settle in for a snooze
Eyelid twitches often happen to people when they are overly tired. Get some restorative sleep.
Step back from stress
Being under stress can lead to a twitch. If you can’t eliminate something causing you stress, find stress-reducing activities to help get rid of the twitch.
Cut back on caffeine
As a stimulant, caffeine can cause eyelid spasms. Limiting your coffee, tea or soda intake may help to reduce eyelid twitching.
“Moisturize” the eyes
In some cases, having irritated or dry eyes can lead to eyelid spasms.

If you have ongoing eyelid twitching and/or gritty, uncomfortable eyes, see your ophthalmologist.

Source American Academy Of Ophthalmology
https://www.aao.org/eye-health/tips-prevention/how-to-stop-eye-twitching