Changes in refractive error for exotropes treated with overminus lenses.

The refractive changes of pediatric patients who were prescribed overminus lenses for exotropia were evaluated. Overminus lenses means additional minus power over the lenses required to correct the refractive error at distance. Forty exotropic patients, ages 1 to 15 years, were prescribed overminus lenses (-0.50 D to -3.75 D) for a period of 9 to 86 months. A small but significant correlation was found between the initial refractive error and the mean annual change toward myopia. Other factors such as age when treatment was given, duration of therapy, amount of overminus, and the amount of the exodeviation had little effect on the rate of myopic change. The mean annual changes in refractive error for hyperopes (-0.13 +/- 0.44 D, N = 15), emmetropes (-0.26 +/- 0.37 D, N = 17), and myopes (-0.75 +/- 0.77 D, N = 18) were similar to values reported in the literature for nonexotropic children.