G'day Kat,Since you have not really pushed the (somewhat separate) issue of girls vs boys in this regard (remember: "Girls who wear glasses, never get passes"?) I might mention the Rudyard Kipling wrote an autobiographical short story about his time sent back to England with his sister while his parents remained in India.
The family (aunt & uncle?) that looked after them adored the sister ... and paid little attention to him. He was doing badly in school and so was banished to the back row of the classroom ... from where he couldn't see anything written on the blackboard. Fortunately for young Rudyard, the fact that he was myopic was eventually realised and he did well once he got glasses.
I doubt that the schooling, medical - or such public health systems as existed in decades past - even believed that children were anything less than in perfect health ... until it proved to late!
Regards,
Bob Bolton