VERY Important! Buy a pair of POLARIZED sun glasses!
There is truly a difference. Polarized is NOT a brand or trade name. It is a real difference in the type of lens.
Want to prove it? Go to place that sells sun glasses and hold up TWO pairs of Polarized glasses. Put one in front of the other as you look through them, and then turn ONE pair 90 degrees. You will see that it totally blacks out. Regular sun glasses will NOT do this, even the most expensive ones.
This makes a HUGE difference in relief from glare and the eye fatigue it causes.