Overcorrecting minus lens therapy for treatment of intermittent exotropia.

The purpose of this paper is to determine the value of overcorrecting minus lenses in treating children with intermittent exotropia. The aim with this therapy is to secure an increase in the quality of fusion and to induce a quantitative decrease in the angle of strabismus. Thirty-five children were treated with 2.00 to 4.00 diopters of overcorrecting minus lenses for a median of 18 months duration. Of these, 46% had an improved quality of fusion during therapy; 26% had an improved quality of fusion and also had a quantitative decrease in their angle of deviation; and 28% had an inadequate improvement in their quality of fusion and decrease in the angle of their deviation with this therapy. Two children went from intermittent exotropia to esotropia while wearing their minus lenses--both had high accommodative-convergence/accommodation ratios (11.5 delta/1D and 10.7 delta/1D). Seventy percent of good responders who were followed for at least 1 year after discontinuing the therapy maintained a qualitative or quantitative improvement in their intermittent exotropia.