Parents often become concerned when they observe their baby’s eyes briefly drifting inward or outward. This appearance, commonly called “cross-eyed,” refers to eye misalignment where both eyes do not look in the same direction simultaneously. While alarming, this is often a normal, temporary part of an infant’s visual development. Understanding the difference between this transient occurrence and a true alignment issue is important.
Why Infant Eye Crossing Is Often Normal
The occasional eye crossing seen in newborns and young infants is frequently a result of their developing visual system learning to work together. The six extraocular muscles that control each eye’s movement are not fully coordinated at birth, meaning the eyes can sometimes move independently of one another. This lack of coordination leads to the brief, intermittent drifting or crossing that is a common sight in the first few months of life.
These transient misalignments are particularly common when a baby is tired, overstimulated, or trying to focus closely on an object near their face. The eye muscles and the visual pathways connecting the eyes to the brain are rapidly maturing during this time, and most babies gain consistent control and the ability to move their eyes together by about four to six months of age.
Another frequent reason for the appearance of crossed eyes is pseudostrabismus, or false strabismus. This is not a true alignment problem but an optical illusion caused by the baby’s facial structure. Many infants have a wide, flat nasal bridge or prominent epicanthal folds (small folds of skin at the inner corner of the eyelids). These features cover the white part of the eye near the nose, making the eyes look turned inward even when they are straight. As the child grows, these folds become less prominent, and the illusion disappears, often by 12 to 18 months.
Recognizing True Strabismus and Warning Signs
While brief, occasional crossing is normal, true strabismus is a genuine misalignment where the eyes point in different directions. Strabismus occurs when the controlling muscles do not work together, preventing the eyes from focusing on the same point simultaneously. This misalignment can be constant or intermittent, affecting one eye or alternating between both.
A major warning sign is eye crossing that persists past the four-to-six-month mark, as the eyes should be consistently aligned by this age. If the crossing is frequent, lasts more than a few seconds, or is constant, professional attention is warranted. Consistency is also concerning, such as when the same eye always turns inward (esotropia), outward (exotropia), upward (hypertropia), or downward (hypotropia).
True strabismus poses a risk because the brain receives two different images, which can cause confusion and double vision. To resolve this, the developing brain may begin to ignore the image from the misaligned eye, a condition called amblyopia or “lazy eye.” If left untreated, amblyopia can lead to a permanent reduction in vision and affect depth perception, making early detection extremely important.
Diagnosis and Early Intervention
If parents observe persistent eye misalignment after the first few months, they should consult their pediatrician for an initial assessment. If a problem is suspected, a referral to a pediatric ophthalmologist or an optometrist specializing in children’s vision is necessary for a comprehensive examination.
The eye specialist uses various tools to differentiate between pseudostrabismus and true strabismus. A common method is the light reflex test, where a light is shone into the eyes to observe where the reflection falls on the cornea; in an aligned eye, the reflection appears in the same spot on both eyes. Other diagnostic procedures include the cover/uncover test and tests to measure visual acuity and refractive errors, such as farsightedness.
Treatment for strabismus is most effective when initiated early, before the visual system is fully mature. Treatment options vary depending on the severity and cause. They often include corrective lenses, which can sometimes fully correct misalignment caused by farsightedness. Other interventions involve patching the stronger eye to force the weaker, misaligned eye to work harder, or vision therapy to improve eye coordination. If non-surgical methods are insufficient, eye muscle surgery may be performed to adjust muscle tension and straighten the eyes.