Which statement best describes Infantile ET compared with Infantile XT regarding constancy and laterality?

• A. Infantile ET is more likely to be constant and unilateral
• B. Infantile ET is more likely to be alternating
• C. Infantile XT is more likely to be constant and unilateral
• D. Infantile XT is more likely to be alternating

Answer: (A)

Infantile misalignments show distinct patterns in how stable the deviation is and which eye is affected. Esotropia that appears very early tends to stay fixed in one eye—a constant inward turn in the same eye—because the early disruption of binocular development creates a persistent inward pull that the visual system doesn’t easily compensate for. This makes the condition typically unilateral and constant.

Exotropia that appears in infancy, on the other hand, more often shows variability: the eyes can alternate fixation or drift intermittently. The brain can switch which eye is the fixating one, leading to alternating or nonconstant outward deviation rather than a fixed unilateral one.

So the statement that infantile esotropia is more likely to be constant and unilateral aligns with the usual early, fixed-in-one-eye pattern, whereas infantile exotropia tends to be more intermittent or alternating.