From a safety standpoint you need to wear glasses to protect your eyes from the hook.
This what a pheasant tail nymph looks like when it hooks your eye.
This is how your eye will end up.
They might as well be polarized to cut out reflected glare.
They might as will be tinted to help you pick out fish. The best tint for most freshwater situations is copper tinted lenses.
So at a minimum get a pair of copper tinted polarized lenses.
Expensive polarized glasses are better without question and in my opinion glass senses are better than plastic. Even if you cannot afford the best or even the better glasses, do get a pair of polarized glasses.