Eye care and tests
There has been much discussion about eyesight improving or deteriorating at fairly short intervals. I haven't yet seen any reference to hydration relative to ocular accuity.
My eyes dimmed due to normal wear and tear at the age of 53, so I am now compelled to CARRY glasses for near vision (not WEAR them?).
The next 2 AvMeds carried out by the same doc. showed that now I don't need to carry them! Too late to remove it from my Class 1 Med cert but interesting nonetheless. The conclusion we came to is that due to dehydration (arrived straight from 12 hr night flight), the check that necessitated my "carry glasses" anotation, was considerably worse than when I presented myself subsequently properly rested, hydrated and alcohol-free.
An example that may demonstrate this to you, is how difficult it is to read tiny print first thing in the morning after a 'session', but it becomes quite easy to read in the afternoon when the H20 levels are back to normal.