Myokymia or eye twitching is a very common eye condition. When you have this condition you will experience repetitive involuntary spasm of the eyelid muscles. A twitch can occur in both the upper and lower lids. Usually these spasms are very mild. But in rare cases people may experience a strong spasm that may cause both eyelids to close completely. This condition is called blepharospasm and it causes chronic and uncontrollable winking or blinking. Most eye twitches don't stay for long but sometimes an eyelid twitching can last for weeks or even months. Eyelid spasms typically are painless and harmless