Had the inverse situation observed too. One of my friends has been writing code intensely since at least the age of 11, still spending tons of time in front of

Had the inverse situation observed too. One of my friends has been writing code intensely since at least the age of 11, still spending tons of time in front of the screen. Never needed glasses in his entire life. And then there is me, who had very limited access to screen time as a kid, and I still ended up needing glasses around the age of 15 (despite none of my parents needing glasses, which goes to show that "genetic" doesn't necessarily mean something as simple as "your parents are this way, so you are bound to be the same way"). I am not a doctor, but imo it is similar to a lot of other health concerns. Predominantly genetic, but you can still affect the outcome in slight ways and improve your chances a bit. Personal example: my grandfather who has been smoking at least a pack a day since the age of 9, and he is still doing way better in his 80s than majority of people his age. Working in the garden (even physically demanding stuff, like preparing the soil for potatoes every summer), fully mentally sound, etc. On another hand, you have plenty of young people who do everything right (no smoking, healthy diet, regular proper exercise, etc.) falling due to random health ailments. Which goes to show that while taking care of yourself is important and beneficial, the luck of hand you got can override it all in either direction at any moment.