The most common type of eye twitching is called blepharospasm, which is actually a twitching motion of the eyelid and not the eye itself.
Generally speaking, blepharospasm is brought on by eye fatigue or stress, and it goes away quickly when you have time to rest. If this is the case, you may notice that the twitch is worse after, for example, a long day staring at a computer screen. Other common causes that are associated with blepharospams include caffeine and alcohol consumption, eye allergies (such as seasonal allergies), and dry eyes.
I would recommend that you go to see your primary care doctor
or your eye doctor
about this condition. They will be able to examine your eyes and help discover if there is a treatable reason for your eye twitch. For example, if you have eye allergy problems, this is something that can be cleared up easily with simple medications.
If your eye twitch is actually motion back and forth of the eye itself and not of the eyelid, this could be nystagmus. Nystagmus is sometimes a symptom of a serious medical problem and therefore it also requires evaluation by your eye doctor or your primary care doctor as soon as possible.