With reading glasses, the powers are particularly adjusted for the reading distances, But if you use it to see things far away which is more than the certain distance , it will blurry your eyes .If you don't need them ,don't wear them .Wearing it once for 6 hours may not affect your vision much .
If you have perfect vision and have to wear computer glasses, why not choose non prescription glasses for look? Non prescription won't hurt your eyes. But if you wear reading glasses, it is likely cause you vision blur, eye aches or even headaches. So, be good to your eyes. Now, it is easy to buy non prescription glasses.