Growing up in the 70s, it was a common admonishment to not read in bed because it would ruin your eyesight. I always found that super duper weird, right up there with masturbating making you blind. Old creeps making shit up to excuse being controlling assholes seems to be a time honoured tradition.
In 1908 the Lancet called for an 18+ age limit on reading in bed for U.K. children.
