Association of ocular dominance and myopia development: a 2-year longitudinal study.

PURPOSE To investigate the effect of ocular dominance on myopia development. METHODS One hundred seventy-eight myopic children (age range, 7-13 years) were recruited for a 2-year longitudinal study. The development of myopia was evaluated by the change of objective refractive error, determined with cycloplegic autorefraction, and axial length, determined with A-scan ultrasonography. Ocular dominance was determined with the hole-in-the-card test. The change in refractive error and axial length between dominant and nondominant eyes were compared by using the paired t-test. RESULTS Twenty-nine subjects were lost to follow-up, and 19 reported poor compliance of wearing spectacles. The mean age of the retained 130 subjects was 10.9 +/- 1.6 years on entry. Sixty-nine (53.1%) subjects were boys. The mean refractive error of the two eyes was -1.73 +/- 0.69 D in spherical equivalent refractive error (SE) and the average anisometropia was 0.22 +/- 0.19 D. The percentages of right dominance, left dominance, and alternating ocular dominance were 64.6%, 34.6%, and 0.8%, respectively. After a 2-year follow-up, the mean change in SE was -1.34 +/- 0.59 and -1.33 +/- 0.64 D in the dominant and nondominant eye, respectively (P = 0.72). The mean increase in axial length was 0.67 +/- 0.42 and 0.64 +/- 0.37 mm, respectively (P = 0.48). CONCLUSIONS The findings demonstrated no statistically significant effect of ocular dominance on the development of myopia over a 2-year period. There was no sufficient evidence to support the idea that bias is introduced into myopia intervention clinical trials when myopia progression is evaluated without consideration of potential effects of ocular dominance on refractive development.