A sniper should have sharp / good eyeslight for obvious reasons.
As mentioned in my previous post, i have not seen or heard of a
sniper who are "4 eyes" during my NSF and reservist as a sniper
pc.
Practical examples why a SAF sniper cann't / shouldn't wear
glasses:-
1. If one does not handle / hold the T-bolt rifle properly during
firing, one may suffer a "sniper eye injury", term we use in sniper
community in saf (not sure about other countries). Basically, the
recoil from firing is so strong that the scope of the rifle hits
the shooter's eye causing "blue black". Hmmm imagine what will
happen to a "4 eye" shooter glasses.
2. Depending on the situation, a sniper may need to dig a "sniper
trench" and stay in the trench for hours if not days. The "hole" is
so humid that the len on rifle's scope, bino and spotter will fog
up. Surely a "4 eye" shooter will face serious problems in such
situtaion.
3. One needs to have a good judgement of distances.
Of course one may argue that he can wear contact lenses 
