The appearance of crossed eyes in an infant often causes concern for parents. This common phenomenon is usually not a genuine problem but an optical illusion known as pseudostrabismus. The term means “false strabismus,” describing a situation where the eyes appear misaligned or crossed, even though they are perfectly straight. This occurrence is a normal developmental stage for many babies.
What Causes the Appearance of Crossed Eyes?
The illusion of crossed eyes stems from specific, temporary features of the infant face. The primary cause is the presence of prominent epicanthal folds, which are folds of skin covering the inner corner of the eye. These folds are noticeable in young babies who have not yet developed a prominent bridge to their nose.
A wide, flat nasal bridge contributes significantly to this visual effect. When the nasal bridge is flat, the epicanthal folds cover more of the white part of the eye (sclera) closest to the nose. This lack of visible sclera makes the pupil appear to be turning inward toward the nose, an appearance called pseudoesotropia.
The deception is particularly noticeable when a baby looks sideways. The epicanthal fold obscures the inner corner, giving the false impression that the eye is turning inward more than it is. Despite the appearance, the eye muscles are working correctly, and both eyes are focused straight ahead and moving together.
The Expected Timeline for Resolution
Pseudostrabismus resolves naturally as a result of the child’s facial growth and maturation. As the child grows, the facial structure changes, altering how light and shadow interact with the eyes.
The most significant change involves the elevation and narrowing of the nasal bridge. As the bridge of the nose becomes more defined, the skin around the inner eye is pulled taut, causing the epicanthal folds to recede. This recession exposes more of the white sclera on the inner side of the eye.
The typical age range for resolution is generally between 18 months and three years old. Some children may show improvement earlier, especially as the nose begins to take shape around the first year. This is a gradual process that correlates with overall physical milestones, and the illusion fades as the face assumes a more mature contour.
Distinguishing False from True Strabismus
While pseudostrabismus is benign, it is important to differentiate it from true strabismus, which is a physical misalignment of the eyes. True strabismus occurs when the eyes do not work together, causing one eye to turn in (esotropia), out (exotropia), up, or down. If left untreated, true strabismus can lead to permanent vision issues, such as amblyopia (“lazy eye”).
Pediatricians and ophthalmologists use the corneal light reflex test, also known as the Hirschberg test, to make this distinction. During this test, a light is shone directly into the child’s eyes. In a child with pseudostrabismus, the light reflects symmetrically in the exact same spot on the surface of both corneas, confirming correct alignment despite the appearance.
If true strabismus is present, the light reflection will be asymmetrical, appearing centered in one eye but noticeably off-center in the misaligned eye. Parents should seek an evaluation from a pediatric ophthalmologist if they observe specific warning signs that suggest a true alignment problem.
Warning signs that warrant immediate attention include:
- The eyes consistently crossing or turning after four to six months of age.
- One eye constantly turning in or out, not just occasionally.
- The child frequently tilting their head to focus on objects.
- Persistent squinting or frequently covering one eye.
- Appearing to have difficulty with depth perception.