Joined the mob at 17, at Raleigh I was taken out of training for a few hours and taken to Plymouth Hospital for extra eye tests (found out the medical ones were not done correctly), was told eyesight OK but would probably need glasses at 21. 21 came and eyesight ok, never needed glasses during my career.
Was told peoples eyesight start to go down hill at 40, as If by magic I had an eye test just as I left the mob at 40, bang, glasses required!!
Now I'm 53 and have to use my phone camera to read cooking instructions on packages (only because I don't carry my glasses around, they are left in my office in the loft

)
Also got hayfever for the first time at around 38 (Waddington Detachment), and it appears to get worse each year!!!