An involuntary eye twitch following a head injury often prompts concern about a concussion, medically known as a mild traumatic brain injury (mTBI). A concussion disrupts normal brain function and can cause a variety of neurological and visual symptoms. This article clarifies the distinction between a common, harmless eye muscle spasm and the specific visual changes that signal a concussion. Understanding these differences helps determine when to seek medical attention.
Understanding Benign Eye Twitching
The common eye twitch is known as eyelid myokymia, a repetitive, involuntary spasm of the orbicularis oculi muscle. This muscle contraction is harmless, temporary, and usually affects only one eyelid. Myokymia is a sign that the eyelid muscle is fatigued or irritated, not a symptom of a significant medical disorder.
These minor twitches are triggered by lifestyle and environmental stress. Common causes include lack of sleep, high intake of caffeine or alcohol, and physical or emotional stress. Eye strain from prolonged computer use or reading, or irritation from dry eyes, can also lead to these localized spasms. The spasms resolve on their own once the underlying stressor is reduced, and they do not indicate brain damage.
Eye Twitching and Concussion: The Connection
Isolated, minor eye twitching (myokymia) is not a reliable diagnostic indicator of a concussion. When myokymia occurs after a head injury, it is often incidental. It is more likely caused by the stress, anxiety, or fatigue associated with the trauma itself, rather than direct brain damage. The brain works harder to compensate for the injury, and this increased effort can lead to generalized fatigue that triggers the benign muscle spasm.
In rare instances, more severe, sustained, or widespread facial spasms may indicate a serious neurological issue involving the facial nerve or brainstem. If the twitching is forceful, involves the entire side of the face, or causes the eyelid to close completely for an extended period, it may signal a condition like hemifacial spasm or blepharospasm. Any new and severe facial movement disorder following head trauma warrants a thorough neurological evaluation.
Vision Changes That Signal a Concussion
While isolated eye twitching is rarely a concern, a variety of other ocular and visual processing symptoms are commonly reported after a mild traumatic brain injury. These issues arise because a concussion disrupts the brain pathways that control vision and eye movement, not the eye itself. Approximately 90% of people with a concussion experience some form of visual symptom.
One common symptom is photophobia, or extreme sensitivity to light, which makes bright or fluorescent lighting uncomfortable. This occurs because the injury can affect pain-sensitive areas in the brain involved in light perception. Many people also experience issues with accommodation, which is the eye’s ability to quickly change focus, often resulting in blurred vision when focusing on near objects.
Concussions frequently cause problems with binocular vision and oculomotor function, which involves the coordination and movement of both eyes. This can manifest as difficulty smoothly following a moving object (smooth pursuit issue), or an inability to quickly shift gaze between targets (saccadic dysfunction). Another common issue is convergence insufficiency, where the eyes struggle to turn inward to maintain focus on a close object. These visual processing deficits can lead to eye strain, double vision (diplopia), headaches, dizziness, and difficulty with reading.
Seeking Medical Evaluation
Knowing when to seek professional medical attention after a head injury is important, regardless of whether eye twitching is present. Certain symptoms, often called “red flags,” indicate a potentially more severe brain injury that requires immediate emergency care.
These red flags include a worsening or persistent headache that does not stop, repeated vomiting, or loss of consciousness that lasts for more than one minute. Other definitive signs that warrant an immediate emergency room visit are seizures or convulsions, slurred speech, and an inability to wake up or increased confusion. Unequal pupil sizes, where one pupil is noticeably larger than the other, is a particularly concerning red flag for severe trauma.
Any persistent visual disturbance, such as double vision, significant light sensitivity, or persistent difficulty tracking objects, should be evaluated by a healthcare professional soon, even if it is not an emergency.