The rate of myopia progression among Chicago-area kids more than doubled during the COVID-19 lockdowns when compared to the same kids during the year before the lockdowns, according to a new peer-reviewed study.

Myopia, or nearsightedness, is growing more common among children, according to the American Academy of Ophthalmology. Though estimates vary, nearly half of the world’s population is expected to have myopia by 2050.

The study authors — who published their findings on Nov. 18 in the British Journal of Ophthalmology — looked at eye exam results of 2,064 Chicago-area kids ages 2-17 from January 2019 through March 2021.

They compared the differences in exam results from 2019 to 2020 — before the COVID-19 lockdowns — with the differences in exam results from 2020 to 2021 when COVID-19 lockdowns were in effect.