congenital strabismus

Congenital strabismus is the older name for infantile esotropia syndrome, the most common cause of a constant strabismus that begins before 1 year of age. The old name is misleading, because the deviation is not usually present at birth.¹ Infantile esotropia is defined as a manifest esodeviation with onset between birth and 6 months of age, and the term is preferred over the older congenital esotropia.²

The angle is typically larger than 30 prism diopters, with cross-fixation, little or no binocular vision, and a refractive error that is normal for age.^2,3 Optokinetic nystagmus is asymmetric.² Inferior oblique overaction, dissociated vertical deviation and fusion maldevelopment nystagmus, formerly called latent nystagmus, often appear after the first year of life.³

Once any amblyopia and significant refractive error have been corrected, the eyes should be surgically aligned within 4 months of the onset of constant esotropia, because alignment in that window may give a better sensory outcome and binocular function.⁴ An acceptable result is alignment within 8 prism diopters with peripheral fusion and central suppression, even though bifoveal fusion is not achieved.⁴