Seeing a baby sleep with their eyes partially or fully open can be unsettling for any parent or caregiver. This phenomenon, which can make the infant appear to be staring or awake, is scientifically known as nocturnal lagophthalmos. In infants, it is overwhelmingly a temporary and benign part of development. This common occurrence reflects the unique way a baby’s body and brain manage their earliest sleep cycles. Understanding the underlying biological mechanisms can help normalize this behavior.
The Core Biological Reasons
The primary biological explanation for this open-eyed sleeping is rooted in the immaturity of the infant nervous system and their sleep architecture. Newborns spend a significantly higher proportion of their rest time in the active sleep phase, comparable to Rapid Eye Movement (REM) sleep in adults. During this stage, the brain is highly active, causing rapid eye movements beneath the eyelids, occasional twitches, and reduced muscle tone.
The neural pathways coordinating the complete closure of the eyelids are still developing in early life. This incomplete control over the eyelid muscles results in physiological lagophthalmos. Because the signal to fully seal the eyelids is not consistently executed, the eyes remain fractionally open, sometimes revealing a sliver of the eyeball.
This developmental difference, combined with the high volume of active REM sleep, means the eyes are not held shut with the same strength as they are in older children and adults. In some cases, a genetic component may also exist, as the trait is more likely if a parent or close relative also sleeps with their eyes open.
Is It Normal When to Seek Help
For the vast majority of infants, sleeping with eyes open is considered normal and is not a cause for medical concern. If the baby is otherwise thriving, feeding well, and meeting expected developmental milestones, this habit represents a quirk of an evolving sleep cycle. Medical professionals regard it as a normal variant of infant sleep behavior, requiring no intervention. The baby is still achieving restful sleep, and the behavior does not indicate a sleep disorder.
However, there are rare instances where this behavior may warrant a consultation with a pediatrician. Parents should seek medical advice if the eyes appear red, dry, or visibly irritated upon waking, suggesting a lack of proper lubrication during sleep.
Signs Requiring Medical Attention
A check-up is necessary if the open eyes are accompanied by other symptoms, including:
- The eyes are open 100% of the time.
- Unusual facial movements.
- Labored breathing.
- Difficulty waking the infant.
In extremely rare circumstances, persistent lagophthalmos can be linked to conditions affecting facial nerves or a congenital abnormality of the eyelid structure, which a medical professional can assess.
Developmental Timeline and Simple Management
This temporary sleep behavior typically resolves on its own as the baby’s nervous system matures and their sleep patterns consolidate. Parents often notice a reduction in frequency around six months of age, as the amount of active REM sleep begins to decrease. Most infants naturally outgrow this trait entirely by the time they reach 12 to 18 months old.
Simple Management Tips
Simple environmental adjustments can help ensure the baby remains comfortable. Because open eyes expose the surface to air, parents should ensure the crib is not placed directly beneath a vent or fan that could increase dryness. If the sight is bothersome, a caregiver can gently stroke the baby’s eyelids downward once they are fully asleep, prompting them to close. No special medical treatment is required, as the body’s natural mechanisms protect the eye surface until the habit fades.