Myopia and cognitive performance: Results from the gutenberg health study

Abstract

Purpose. To analyze the association between myopia and cognitive performance. Methods. A cohort of the population-based Gutenberg Health Study included 3819 eligible enrollees between 40 and 79 years. We used the Tower of London (TOL) test to assess cognitive performance. Myopia was defined as a spherical equivalent (SE) ≤ 0.5 diopters (D) via noncycloplegic autorefractometry. We conducted linear mixed models with the SE as the dependent variable and the age, sex, duration of education, and TOL score as covariates. Results. Complete data were available for 3452 participants (90.4%). The mean TOL score was 14.0 ± 3.9 in the myopes versus 12.9 ± 4.0 in the nonmyopes (P < 0.001). The mean TOL score increased with the magnitude of myopia: it was 13.9 ± 3.9 in low (less than 3 D); 14.2 ± 3.7 in moderate (between 3 and 6 D); and 14.6 ± 3.5 in high myopia (6 D and greater; P < 0.001). Both the duration of education and cognitive performance were correlated with the magnitude of myopia (r = 0.21, P < 0.001 and r = 0.15, P < 0.001, respectively). In a linear mixed model, the duration of education significantly predicted myopia (b = 0.14; t = 7.55; P < 0.001), whereas cognitive performance did not (b = 0.017; t = 1.26; P = 0.207). There was a significant effect of age on the SE (b = 0.049; t = 9.89; P < 0.001). Conclusions. When regarded separately, cognitive performance is linked to myopia. However, duration of education, which may be directly related to the risk factors for myopia, is more directly and strongly related to myopia than is cognitive performance. Cognitive ability may be associated with myopia primarily through its impact on level of education.