Reaching for the Holy Grail in strabismus: the mechanism underlying infantile esotropia

Infantile esotropia is not present at birth. The misalignment is acquired, usually showing up by 6 months of age. It is now well known that decorrelation of the two eyes’ images reaching the brain impairs the development of horizontal connections between the ocular dominance columns in specific layers of area V1 of the visual cortex. Without these horizontal connections, there is persistence of pursuit asymmetry and deficient gaze holding, resulting in slow, involuntary adduction, usually depression, and intorsion of the fixing eye, leading to corrective saccades producing latent nystagmus, now called fusion maldevelopment nystagmus.