esotropia

Esotropia is a manifest inward deviation of the eyes, with visual axes that do not intersect at the point of fixation.¹ Esotropia differs from esophoria, held latent by fusional divergence, and from intermittent esotropia, controlled by fusion only part of the time.²

Esotropia arises from innervational or mechanical factors, or a combination of both.² The images from the two eyes are misaligned. The patient sees double or, more often in children, suppresses the image from the deviating eye. A childhood esotropia may follow a failure of binocular fusion to develop normally, or an oculomotor imbalance from anisometropia. In adults, poor vision in one eye, weakness or mechanical restriction of the extraocular muscles, or damage to their nerve supply can produce a manifest deviation.¹

Esotropia is concomitant if the angle varies by no more than 5 prism diopters across horizontal gaze positions. The deviation is incomitant if abnormal innervation or restriction makes the angle differ with gaze.¹ Early-onset (essential infantile) esotropia develops within the first 6 months of life in an otherwise normal infant. Infrequent episodes of convergence are normal up to 4 months.¹ In the presence of esotropia, the full cycloplegic hyperopic correction is prescribed, even under the age of 2 years.¹