In 1968, I was treated by an optometrist who said that nearsightedness is learned. He was regarded as a crank.
He said that kids should take breaks from reading. They should spend more time outdoors. He was regarded as a crank.
He prescribed corrective lenses for me at age 26 that focused only at two feet. He told me not to read with my distance lenses. He was regarded as a crank. But for the next three decades, my nearsightedness did not increase, as it had over the previous 15 years.
Guess what? The crank was right. Nearsightedness is learned.