Overcorrecting minus lens application for intermittent exotropia

Abstract

Purpose: To determine the value of overcorrecting minus lenses in the treatment of intermittent exotropia. Methods: 22 patients ranged in age from 2 to 14 years (mean± SD, 6.4 ± 1.1) were divided into three groups according to their pretreatment deviations measured with alternate cover test and prism bar. Group I included seven patients with exotropia more than 25D , Group II included seven patients between 20-25D exotropia, and Group III consisted of eight patients less than 20D exotropia. They were followed 6 to 20 months (mean, 14 months) after the application of overcorrecting minus lenses in between -0.50 and -4.0 diopters (mean, -1.85) which were added to baseline refractive error. Success was defined as a conversion to orthophoria, pure exophoria and/or intermittent exotropia of 10D or less. Results: The success rates were 42.8% in Group I, 57.1% in Group II, 87.5% in Group III. The overall success rate was 63.6%. Conclusion: Overcorrecting minus lens treatment in intermittent exotropia can delay or eliminate surgical treatment. As the deviation size of intermittent exotropia decreases the success rate increases.