SUMMARY
Purpose:
To determine the effect of experimentally-induced anisometropia on binocular function in normal and mildly amblyopic children.
Methods:
A total of 20 nonstrabismic patients ranging in age from 6 to 12 years were studied. All had at least 40 arc seconds of stereopsis. Ten subjects had normal visual acuity (controls), and 10 had mild unilateral amblyopia. Binocular interaction was assessed by measurement of stereoacuity (Titmus circles) and Worth four-dot fusion test. Unilateral myopia, hyperopia or astigmatism (at 90 and 45 deg) were induced in each subject using trial lenses, ranging from 1 to 4 diopters.
Results:
All subjects, regardless of group, showed a decline in binocularfunction with increasing levels of anisometropia, as evidenced by increased suppression on Worth 4-dot and decreased stereoacuity on Titmus testing. There was no difference in median stereoacuity between groups for any type or level of anisometropia.
Conclusion:
Even low degrees of induced anisometropia may cause significant abnormalites in binocular function in children. Preexisting mild amblyopia does not seem to significantly affect this relationship.
Keywords:
Binocularity; Anisometropia; Amblyopia