Gender issues in myopia: a changing paradigm in generations.

Myopia is becoming an important cause of visual impairment. Determining risk profiles will help to develop targeted prevention strategies. This study aims to explore the difference in myopia development between genders in two cohorts representing different generations, and to assess whether hypothetical interventions targeting education or lifestyle factors would reduce a gender gap. This study included two Dutch population-based cohorts; 11,109 adults aged ≥ 45 years from the Rotterdam Study I-III born between 1887 and 1960, and 7229 children from the birth cohort Generation R study born between 2002 and 2006 at age 9-13 years. Sequential G-estimation was used to estimate changes in gender-specific myopia prevalence, incidence and spherical equivalent if hypothetical interventions such as education and lifestyle changes would have been implemented. Myopia prevalence was 32.3% in men and 29.3% in women in the generation born between 1887 and 1960 (0.23 dioptre difference in spherical equivalent; p < 0.001); while this prevalence was 20.2% in boys and 24.7% in girls born between 2002 and 2006 at age 13 (0.15 dioptre difference in spherical equivalent; p = 0.02). In the older generation, hypothetically intervening to lower education reduced the difference between genders by -52.4% (-108.0%; -13.2%) for spherical equivalent and - 53.0% (-112.0%; -11.6%) for myopia. In children, hypothetically intervening on reducing reading time (-50.0%, 95%CI=-267.5%; 33.8% for spherical equivalent) and number of books read/week (-76.8%, 95% CI=-349.9%; 20.2% for spherical equivalent) was most prominent, but not statistically significant. The results show that men had a higher prevalence of myopia in our study of older generations; while girls had a higher prevalence in the young generation. Our hypothetical interventions suggest that these generation-specific gender preponderances were largely due to education and, possibly, lifestyle factors in youth.