Twitching of the eye almost always occurs in the muscles of the eyelid. Because they press on the eye it may feel as though the eyeball itself is moving Minor eyelid twitches require no treatment as they usually resolve spontaneously. Reducing stress, using warm soaks, in some cases it occurs because of irritation in the eye, which results in twitching of the eyelid. However, if the eye is comfortable it is more likely that it is a simple muscle spasm, which may be related to stress or fatigue or in, many cases happen spontaneously without any known cause. Eye Twitching should resolve on its own it does not it certainly is worth a comprehensive eye examination to ensure that no other problem is occurring in the eye.
I found this answer when I googled eyball twitching. Sometimes it can be when your eyes have been strained, my eyes do that sometimes after I have been on the computer for hours in low light.