Eye lid twitching is usually a sign of fatigue and nothing more, similar to the way that other small muscles in your body can have minor spasms when they are tired. That is why you notice the symptoms most prominently at night, and why the small muscles are most readily fatigued. It is also notable that your symptoms occur when you are actively using your eyes in a focused manner that will more easily fatigue them. Make a note of your twitches, and see when and where they occur to see if these generalities are true for you.
In some other, extremely rare, cases, eye lid twitching can be a sign of other illnesses. If you find that larger muscle groups are also having spasms, or if there is any change in your vision, or any other symptoms associated with the twitching, you should speak to your doctor
. Additionally, if you have any family history of muscle disorders, it would be wise to discuss these with your doctor as well. Otherwise, observe your symptoms for signs of a pattern, as you have been doing, and discuss this and any changes with your physician at your next physical examination or routine checkup.