Winking is a voluntary movement involving the precise closure of a single eyelid while the other remains open. This action requires isolated muscle control, making it a specialized facial movement. Many people find it significantly easier, or only possible, to wink with one eye. This asymmetrical winking is generally a normal variation in motor skill development, not a sign of an underlying physical problem.
The Anatomy of Winking
The physical ability to wink relies primarily on a specialized muscle called the orbicularis oculi. This muscle is arranged in circular fibers that surround the eye socket, functioning like a sphincter to close the eyelid. When a wink is performed, the palpebral portion of the orbicularis oculi contracts gently to bring the lids together.
The signal to initiate this contraction travels from the brain through the facial nerve, also known as Cranial Nerve VII. This nerve branches out to supply all the muscles of facial expression, including the orbicularis oculi on both sides of the face.
The physical structure of the muscle and the integrity of the nerve are identical on both sides. Both eyes possess the necessary hardware to perform the winking motion. Therefore, the difference in skill is usually not due to a physical deficit in the muscle or nerve pathway itself.
Motor Control and Hemispheric Dominance
The challenge of winking is not the strength to close the eye, but the ability to precisely isolate the orbicularis oculi muscle on one side while maintaining relaxation on the other. This act is categorized as a fine motor skill requiring significant neuromuscular dissociation. The command for this isolated movement originates in the motor cortex, which plans and executes all voluntary movements.
This motor planning is often influenced by hemispheric dominance, which is the tendency for one side of the brain to be more specialized or efficient in controlling certain functions. For most people, the left cerebral hemisphere is dominant, controlling language and the fine motor skills of the right side of the body. This dominance can subtly affect the efficiency of neural pathways.
The pathways that control the preferred winking eye are generally more robustly developed and frequently used, making the action feel automatic. The less successful eye, however, may have pathways that are less practiced in this specific type of isolated activation.
Consequently, the difficulty in winking with the non-dominant eye is typically a matter of motor learning and neural coordination, rather than muscle weakness. The brain struggles to inhibit the simultaneous closure of the opposite eyelid, leading to an awkward half-blink or full-blink instead of a clean, isolated wink. This suggests the issue is a lack of precise motor control rather than an anatomical deficit.
Training the Non-Dominant Eye
Since the inability to wink with both eyes is rooted in motor learning, the skill can often be acquired through targeted practice and repetition. The goal is to forge new, more efficient neural pathways dedicated to the isolated movement of the non-dominant eye. This process requires patience and deliberate focus.
A simple starting technique involves using one hand to gently hold down the muscles around the eye that tends to contract (the dominant eye). This physical inhibition helps the brain focus the neural command exclusively on the target eye, preventing the unintentional co-contraction of the wrong side.
Practicing in front of a mirror allows for immediate visual feedback, which is an important component of motor skill acquisition. Begin by attempting to close the target eye very slowly, focusing intently on the sensation of the muscle contracting in isolation.
The initial attempts may result in the eyebrow raising or the mouth twitching, which are signs of the brain recruiting surrounding muscles to assist. As control improves, the goal is to reduce these extraneous movements, achieving a smooth, isolated closure. Consistency is more important than duration; several short practice sessions throughout the day are often more effective than one long session.
When Asymmetry May Signal a Medical Issue
While a lifelong preference for winking with one eye is normal, any sudden change in the ability to wink or close an eye should be evaluated by a healthcare provider. The difference between benign asymmetry and a medical concern is the onset and the presence of other symptoms.
Medical attention is warranted if a previously functional wink suddenly becomes impossible or weak, especially on one side. This sudden inability to close the eye entirely may suggest an issue with the facial nerve, such as facial nerve paralysis.
Other concerning signs include drooping of the eyebrow or corner of the mouth, facial numbness, or difficulty controlling other facial expressions. If the eye cannot fully close, the inability to protect the cornea from drying out becomes a separate concern. The presence of any new, rapidly developing facial asymmetry requires prompt professional assessment.