“Among Americans, rates of myopia have increased from 25% of people in 1971 to more than 40% today, according to the National Eye Institute. In the major cities of developed Asian countries, the rate exceeds 80% among students as they graduate from high school.” The cause is not completely clear, but experts think it could be a combo of too much smartphone time and not enough exposure to daylight. Elemental: Something Is Causing Our Eyeballs to Elongate.