Retrospective cross-sectional, trend study using a random population-based sample in Olmsted County, Minnesota from 1966-2019.
METHODS: Manifest refractions or lens prescription were converted to spherical equivalent (SE) to estimate prevalence of adult
myopia and high
myopia. Age, sex, race, and visual acuity were recorded. Subjects with SE ≤-0.5 diopters (D) were considered myopic; ≤-6.0 D were considered high
myopia. Exclusion criteria included visually significant
cataract,
pseudophakia, prior
refractive surgery, or age <18 years-old.
RESULTS: Among 81,706 sampled subjects,
myopia prevalence increased from 33.9% (95% CI 31.1-36.8) in 1960s to 57.1% (95% CI, 56.6-57.6) in 2010s (p<0.001). High
myopia prevalence increased from 2.8% (95% CI, 1.95-3.98) in 1960s to 8.3% (95% CI, 8.08-8.62) in 2010s (p<0.001). Both males (32.0%-55.1%, p<.001) and females (40.6%-58.5%, p<.001) experienced increasing
myopia prevalence from 1960s-2010s while males (2.6%-7.4%, p<.001) and females (3.4%-9.1%, p<.001) also had higher high
myopia prevalence rates from 1960s through 2010s. Increasing
myopia and high
myopia prevalence was detected by decade in nearly all age groups (excluding 18-24-year-old high
myopia subjects). White and Asian subjects had the highest
myopia prevalence while Black subjects had the lowest. From the 2000s-2010s, White (53.3%-57.0%, p<0.001) and Black (41.0%-47.0%, p=0.001) subjects had significant increases in
myopia prevalence. Mean SE decreased from the 1960s (-0.42 D; 95% CI -0.59-+2.49) to 2010s (-1.85 D; 95% CI, -1.88-+2.96) (p<0.001).
CONCLUSIONS: From 1966-2019 in Olmsted County, Minnesota, there was a 68% and 199% increase in
myopia and high
myopia prevalence, respectively.