Why Can’t I Close My Left Eye on Its Own?

For most people, the inability to close one eye independently while the other stays open is a perfectly normal quirk of how the brain controls facial muscles, not a sign of nerve damage or disease. In one study that recruited 63 healthy adults, roughly two-thirds could only wink on one side, and the left eye is a particularly common culprit for being the “uncooperative” one. The explanation sits at the intersection of brain asymmetry, eye dominance, and how finely you’ve trained the ring-shaped muscle around each eye. That said, a sudden or worsening difficulty closing one eye can sometimes signal a real neurological issue, so the distinction between lifelong quirk and new symptom matters.

Most People Cannot Wink Both Eyes Equally

If you’ve been quietly embarrassed about this, you’re in good company. When researchers at a university hospital screened volunteers for a brain-imaging study on winking, they found that 41 out of 63 participants could wink only one eye, not both. Just 22 of the 63 could wink bilaterally from the start.¹ That means about 65% of healthy adults share your experience of having one eye that simply won’t cooperate when asked to close on its own. The difference usually isn’t about muscle weakness. Both eyelids can close perfectly well together during a normal blink. The challenge is isolating one side’s closure while keeping the other open, and that turns out to be a surprisingly high-level brain task.

The Muscle Behind the Movement

Each eyelid is closed by a ring-shaped muscle called the orbicularis oculi, which wraps concentrically around the eye from the inner corner to the outer corner. It has orbital sections (the wider ring that squeezes during a hard squint) and palpebral sections (the thinner inner ring responsible for gentle blinks and voluntary winks). The muscle is controlled by the facial nerve, specifically the zygomatic and temporal branches.² The zygomatic branch travels obliquely across the cheek to supply the lower eyelid portion and even part of the upper eyelid’s medial area.³

What makes winking different from blinking is that blinking uses the muscle symmetrically on both sides at once, driven by a brainstem reflex. Winking requires the brain’s cortex to override that symmetry and selectively activate one side while actively suppressing the other. Recent research using distributed sensors placed within the muscle has shown that the orbicularis oculi doesn’t fire uniformly during different eyelid movements. Instead, different segments of the muscle activate in distinct patterns depending on whether you’re blinking, squinting, or winking.⁴ This segmental control means that winking isn’t just “closing one eye.” It’s a coordinated pattern of activation and inhibition across multiple muscle zones, and that pattern is harder to execute on one side than the other for most people.

Your Brain Treats Left and Right Winks Differently

The most revealing explanation comes from brain imaging. When researchers scanned people’s brains while they winked, the activation patterns were strikingly asymmetric. Closing the left eye lit up only the left frontal lobe. Closing the right eye, by contrast, activated both frontal lobes with a stronger signal on the right side.¹ In other words, a right-eye wink recruits a broader network of brain areas, which may give it more cortical support. A left-eye wink relies on a more localized patch of brain tissue and, for many people, that patch alone isn’t enough to pull off the selective closure smoothly.

This isn’t about one hemisphere being “stronger.” It reflects the way the brain organizes fine motor control of the face. Facial expressions are among the most complex voluntary motor acts humans perform, and the cortical circuits that handle them didn’t evolve for party tricks. They evolved primarily for communication. In primates that live in larger social groups, the brain region controlling facial muscles tends to be proportionally bigger, suggesting that fine facial motor control co-evolved with social complexity.⁵ Winking is a side benefit of that elaborate circuitry, and asymmetry in its execution is a natural consequence of how unevenly the brain distributes these control networks.

Eye Dominance Plays a Role

You probably have a dominant eye, just as you have a dominant hand, and it influences which eye you can close independently. Research has found that people tend to wink the non-dominant eye more easily and more frequently than the dominant eye, regardless of whether they’re left- or right-handed.⁶ The logic makes intuitive sense once you think about it: winking means keeping one eye open and one shut. The eye you keep open is the one you want to see through, which is naturally your dominant eye. So your brain has an easier time closing the non-dominant eye because it’s already biased toward relying on the dominant one for vision.

Most people are right-eye dominant, which means most people find it easier to close the left eye. If you’re left-eye dominant, you may find the opposite, that the right eye is the stubborn one. You can check your own eye dominance quickly: extend your arm, point at a distant object with both eyes open, then alternately close each eye. The eye that keeps the object aligned with your finger is your dominant eye. If that’s the right one, you’ve likely found the reason your left eye cooperates with winking while the other doesn’t, or vice versa.

Children Learn This Skill Gradually

If you watch young children try to look through a tube or a telescope, they typically hold it between both eyes rather than bringing it to one. The ability to voluntarily close one eye while keeping the other open develops over childhood through a predictable sequence. Researchers who videotaped 174 children between the ages of 2 and 17 found that kids progress from centering objects between both eyes to turning the head to avoid double vision and eventually to closing one eye entirely.⁷ The fact that this skill follows a developmental timeline rather than appearing all at once tells us it isn’t hardwired. It’s learned motor behavior that relies on brain maturation, and not everyone completes the learning equally on both sides.

This developmental pattern also explains why some adults who “never could” wink one eye may assume there’s something wrong. In most cases, they simply reached a plateau in childhood where one side’s cortical pathway was practiced enough and the other never caught up. The brain didn’t need both, so it didn’t bother refining both.

Can You Train Yourself to Close That Eye?

Yes, and the brain imaging evidence suggests you’re not building a new pathway from scratch. When people who could only wink one eye were taught to wink the other, their brains activated the same cortical areas that naturally bilateral winkers already used. The learning process worked by strengthening existing neural circuits, not by recruiting completely new brain regions.¹ This is encouraging because it means the hardware is already in place. Your brain has the circuitry to close that left eye independently; it just hasn’t been tuned up enough.

Practical approaches tend to start with physically holding the “easy” eye open with your fingers while practicing closing the difficult one. This removes the need for the brain to simultaneously suppress one side and activate the other, letting you focus on just the closure. Over time, you reduce the finger assist. Mirror practice helps too, because visual feedback lets the brain calibrate the motor signal more quickly. Don’t expect overnight results. People in the study above required a training period, and many of the participants never achieved the same smoothness on their trained side as on their natural side. But functional improvement is realistic for most people.

When Difficulty Closing One Eye Is a Medical Concern

Everything discussed so far applies to people who have always had an asymmetry in winking ability. The situation changes if the difficulty is new, worsening, or accompanied by other facial weakness. Several conditions can impair the ability to close one eye, and they require different responses.

The most common acute cause is Bell’s palsy, a sudden weakness of the facial nerve on one side that makes it difficult or impossible to close the eye on the affected side, wrinkle the forehead, or smile symmetrically. Bell’s palsy typically comes on over a day or two and resolves on its own within weeks to months in most cases, though some people are left with residual weakness. If you’ve woken up unable to close one eye and the other side of your face feels stiff or droopy, see a doctor promptly. Early treatment can improve outcomes.

Another condition worth knowing about is hemifacial spasm, which involves involuntary contractions of the muscles on one side of the face, including the eye. Among 215 patients referred for evaluation, about 62% had the primary form, thought to be caused by a blood vessel pressing against the facial nerve where it exits the brainstem.⁸ Hemifacial spasm doesn’t just make it hard to close one eye. It forces the eye shut involuntarily and can interfere with vision and daily life. Involuntary eye closure that disrupted vision was among the most common complaints in patients with the condition.⁹

Synkinesis and Aberrant Nerve Recovery

After facial nerve damage, like from Bell’s palsy or surgery near the facial nerve, some people develop synkinesis, where voluntary movement of one facial muscle triggers involuntary movement of another. A common pattern is oculo-oral synkinesis: you try to smile and your eye closes, or you try to close your eye and your mouth pulls to one side.¹⁰ This happens because regenerating nerve fibers sometimes grow into the wrong muscle, creating cross-wired connections. The result is that voluntary facial movements become coupled in ways they shouldn’t be.

Synkinesis can make it genuinely difficult to isolate eye closure because the brain’s command to close the eye also fires signals to the mouth or cheek. Biofeedback-based rehabilitation has shown promise in reducing this. In one controlled study, patients who received biofeedback training after facial palsy had significantly less synkinesis than those who didn’t, as measured by asymmetry of eye opening width.¹¹ The training works by teaching patients to recognize and suppress the unwanted co-activation before it becomes a permanent wiring pattern.

Congenital Conditions That Affect Eyelid Control

A small number of people have trouble with eyelid closure from birth due to congenital conditions affecting the facial nerve or its brainstem nuclei. Möbius syndrome is the most recognized of these, characterized by non-progressive facial weakness present from birth, often accompanied by limited ability to move the eyes outward. It’s attributed to abnormal development of the facial and abducens cranial nerves.¹² Research has shown that Möbius syndrome involves broader developmental abnormalities of the brainstem beyond just those two nerves, affecting motor nuclei and the long tracts that pass through the region.¹³

Another congenital curiosity is Marcus Gunn jaw-winking synkinesis, in which one eyelid moves involuntarily when the jaw moves, like during chewing. This is an aberrant connection between the nerve that controls jaw muscles and the one that controls the eyelid, present from birth. The condition is thought to involve peripheral nerve miswiring during development.¹⁴ These congenital conditions are rare and typically diagnosed in infancy or early childhood. They’re mentioned here mainly so you can distinguish them from the garden-variety “I just can’t wink my left eye” experience, which is overwhelmingly the benign neurological asymmetry described earlier.

How to Tell the Difference Between Normal Asymmetry and a Problem

The key question is whether the difficulty is lifelong and stable, or new and changing. If you’ve never been able to close your left eye on its own but can close it fine along with the right one during a normal blink, and your face looks symmetric at rest and during smiling, you almost certainly have the normal cortical asymmetry shared by about two-thirds of adults. No workup is needed.

Seek evaluation if any of the following apply:

New onset: You used to be able to close the eye and now you can’t, especially if it came on over hours or days.
Incomplete closure: The eye doesn’t fully shut even during a normal bilateral blink, leaving a gap that exposes the surface. This can cause corneal drying and damage.
Facial asymmetry: One side of your face droops at rest, or you notice weakness when smiling, raising your eyebrows, or puffing your cheeks.
Involuntary movements: The eye twitches or closes on its own, or other facial muscles contract when you try to move the eye.
Accompanying symptoms: Ear pain, change in taste, hearing sensitivity on one side, or numbness can accompany facial nerve problems.

A doctor can distinguish between these causes fairly quickly with a physical exam. If there’s true facial nerve weakness, imaging and sometimes nerve-conduction studies help pinpoint the location and cause. But again, the vast majority of people asking “why can’t I close my left eye on its own?” are describing a normal limitation, not a disease process.

Why the Left Eye Specifically

The left eye comes up more often in this question partly because of the population statistics on eye dominance. Roughly two-thirds of people are right-eye dominant, and since people tend to find it easier to close their non-dominant eye, that means the right eye is more often the one people can wink successfully, leaving the left as the problem child. But the brain-activation data adds another layer. The fact that left-eye winking activates a more focal area of the left frontal lobe, compared to the broader bilateral activation for right-eye winking, suggests the neural command for closing the left eye is inherently less robust in many people.¹ Whether this cortical asymmetry causes the eye dominance pattern, or whether the eye dominance pattern shapes the cortical asymmetry through years of preferential use, remains an open question. Researchers who have studied this relationship have found evidence that motor function can develop in response to sensory function, suggesting the dominance of one eye for seeing may drive the motor circuitry to favor keeping that eye open.⁶

If you’re among the minority who can close the left eye but not the right, you’re likely left-eye dominant, and the same logic applies in reverse. The specifics of which side is which vary from person to person. The principle is consistent: the brain preferentially supports keeping the dominant eye open, making the non-dominant eye easier to close on its own and the dominant eye stubbornly resistant to independent closure.

1
PubMed Central. Cerebral control of winking before and after learning: An event-related fMRI study
2
PubMed Central. Anatomy, Head and Neck: Orbicularis Oculi Muscle
3
PubMed. Facial Nerve Supply to the Orbicularis Oculi around the Lower Eyelid: Anatomy and Its Clinical Implications
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PubMed Central. Human eyelid behavior is driven by segmental neural control of the orbicularis oculi
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PubMed Central. Correlated evolution of brain regions involved in producing and processing facial expressions in anthropoid primates
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PubMed. Does motor cerebral dominance develop secondary to sensory dominance?
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Vision Research. Learning to Look With One Eye: The Use of Head Turn by Normals and Strabismics
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PubMed. The many faces of hemifacial spasm: differential diagnosis of unilateral facial spasms
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Muscle & Nerve. Hemifacial spasm: Clinical findings and treatment
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PubMed Central. Pathogenesis, diagnosis and therapy of facial synkinesis
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PubMed. Biofeedback rehabilitation for prevention of synkinesis after facial palsy
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Brain. Characterization of ocular motor deficits in congenital facial weakness: Moebius and related syndromes
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PubMed. Möbius syndrome redefined: a syndrome of rhombencephalic maldevelopment
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PubMed. Marcus Gunn Jaw-Winking Synkinesis With Ipsilateral Eyelid Myokymia