OK. Thanks for those responses.
Twitching of any muscle can occur and not necessarily be a dangerous symptom. Twitching of muscles can sometimes be triggered by caffeine consumption or poor sleep, and this in particular can affect small muscles such as those of the eyelid. In a case where one is having troublesome twitching, I certainly would suggest taking a week or 2 off of caffeine consumption, to see if that makes any difference. Even if it isn't a cause for the twitching, it could be making it worse. The same goes for poor sleep. You could consider checking with your primary doctor about how to establish good sleep habits, and/or be evaluated for your insomnia to try to improve this issue, since sleep difficulty can also possibly make twitching worse.
Otherwise, there are a long list of conditions that can cause abnormal muscle movements, which can include seizures, metabolic problems such as liver, thyroid, or kidney disease, and other conditions such as Tourette's disease (which normally produce tics rather than twitches, but they can often be confused for each other).
I would suggest that you consider seeing a neurologist if these twitches are not getting better and are bothering you. A neurologist would likely test you for certain medical conditions with blood work, would consider the need for brainwave testing (called EEG) to evaluate for seizure disorders, and would determine if you need any brain imaging for these symptoms. Of course, once the cause is determined, then appropriate treatment can be considered.
I hope this has been useful information for you. Please let me know if there are other questions. If this has been helpful, please rate me highly. Bonuses are appreciated. Best wishes!