The correlation between headache and refractive errors

PURPOSE To compare the prevalence of refractive errors in patients with headache and a control population. METHODS Three hundred ten patients with headache and 843 controls were retrospectively evaluated. Complete oplithalmologic examination was performed in the headache group. Autorefraction was performed in all participants (with cycloplegia under 10 years of age). Myopia was defined as the spherical equivalent refraction of at least -0.50 D, hyperopia as the spherical equivalent refraction of at least +2.0 D, and astigmatism as the cylinder of at least 1.0 D. Main outcome measures were refractive error, anisometropia, and previous miscorrection of refractive error. Chi-square and Student's t-tests were used for statistical analysis. RESULTS Total prevalence of refractive errors was higher in the headache group (p = 0.002). The rate of astigmatism was higher in the headache group (p < 0.0001), while that of myopia and hyperopia were similar in both groups (p = 0.74, p = 0.79, respectively). The rates of compound and mixed astigmatism were higher in the headache group (p = 0.026, p < 0.001, respectively). The rates of anisometropia and previous miscorrection of refractive error were higher in the headache group (p < 0.0001 for both). Children with headache have a statistically significant increased risk of total refractive errors (OR = 1.57, 95% CI: 1.18-2.07), anisometropia (OR = 9.59, 95% CI: 5.72-16.1), and miscorrection of refractive error (OR = 9.57, 95% CI: 5.43-16.9). CONCLUSIONS Compound and mixed types of astigmatism, anisometropia, and miscorrection of refractive error were found more often in patients with headache than in control subjects.