Eyelid tremors, also known as eyelid spasms or myokymia, are involuntary, repetitive movements of the eyelid muscles. These tremors can be annoying and disruptive, causing discomfort and sometimes affecting vision. While eyelid tremors are usually harmless, they can be a symptom of an underlying medical condition or a sign of stress or fatigue. Why Do Eyelid Tremors Happen? The exact cause of eyelid tremors is not always clear, but there are several possible factors that can contribute to these involuntary movements. Some common causes of eyelid tremors include: 1. Fatigue: Lack of sleep, long hours staring at a computer screen, or excessive physical exertion can lead to muscle fatigue, which can trigger eyelid tremors.