Eye Health Epidemic

What's behind the sharp increase in nearsightedness?

- Rebecca Gao

ROUGHLY 42% OF Americans are nearsighted today, compared to 25% in 1971. The World Health Organization (WHO) predicts that about half of the world's population will have myopia, or nearsightedness, by 2050. It's clear that our vision is becoming increasingly blurry, but researchers are only now beginning to understand why.

Generally a childhood phenomenon, myopia happens when the eyeball grows too long from front to back, taking on more of an oval shape versus a sphere. Eyes have a "stop signal" so that they grow proportionally with the head, explains Gregory Schwartz, an associate professor at the Departments of Ophthalmology and Neuroscience at the Feinberg School of Medicine at Northwestern University. However, that signal can be interrupted by genetic and environmental factors, which leads to our eyeballs growing a bit too much, making them too big for the optics (the lens and the cornea, which are responsible for focusing your vision).

The mismatch between the eyeballs and the optics leads to far-off objects looking out of focus. Telltale signs you might have myopia also include headaches, as well as eye strain and tiredness when doing certain activities such as driving or playing sports.