I have glasses for computer use only. For detail work (like aiming the tank gun at long range) I take off my glasses and get close (I'm as near sighted as Mr. McGoo... and that reference tells you I'm older than dirt). If you're getting headaches or fuzzy eyesight, it could mean your prescrition isn't good for the distance between your eyes and the screen. As you get older your accommodation, the ability to change focal distance, essentially goes away. So you need glasses for each specific distance. I have reading glasses, computer glasses, bifocals, and full distance dark glasses.
I would suggest you measure the distance between your eyes and the screen and then visit your ophthalmologist for a checkup and a new prescription.
I have noticed that age is not good for air combat. When I started 22 years ago on Air Warrior version 1.0, I was actually good- hit number one once. Now, with the reaction time of a three toed sloth on sleeping pills, I am considerably worse than average.