Binocularity following surgery for secondary esotropia in childhood

Binocularity was assessed in children who developed large, constant esotropia following bilateral lateral rectus recessions for intermittent exotropia. Nine such patients were identified who warranted medical rectus recession. Seven were finally aligned within 6 prism dioptres after secondary surgery. Stereopsis measured 50 seconds or better in six of these patients and 200 seconds of arc in the seventh. Two patients had residual deviations: one child with 30 prism dioptres of residual esotropia had 400 arc seconds and the remaining patient, with 12 prism dioptres of exotropia and marked anisometropia, did not show stereopsis. Children with constant acquired esotropia for as long as two years may still have normal stereopsis after surgical alignment. The risk of losing binocularity because of a large overcorrection following exotropia surgery may be smaller than previously assumed.