The eyes are one of the biggest tells in poker (and for emotions in general). The biggest reason people have for wanting glasses banned at the poker table is advantage. They can't see their opponent's eyes, thus turning the advantage slightly away from them. When you hide your eyes, you are hiding some emotion. When you hide emotion, your tells are less obvious. Period. Negreanu isn't worried about cheating; he's worried about playing scared against someone wearing glasses. "The majority of the best players in the world don't wear glasses," he says? Wearing glasses makes you a chicken, he says? Not wearing glasses means you man up, he says? Phil Hellmuth (yeah, the 13-time WSOP
bracelet winner) has worn glasses. Hoyt Corkins wears glasses. Chris Moneymaker, Greg Raymer, Jonathan Little, Annette Obrestad, Scotty Nguyen, Chris Ferguson, Dave Ulliottt, Johnny Chan, Marcel Luske (though upside down), Sam Farha, Stu Unger... I'll just stop here.
Serious poker players who wear glasses don't wear them as a fashion statement (if they do, they need to stop, immediately). They wear them to keep themselves in a comfort zone, knowing a main source of tells is hidden away from their opponents, and many pros do too. TV may have made it cool to wear glasses at the table, but we are in 2014 - the novelty of it is gone. The benefits of it are here to stay.
For those of you that do not wear glasses at the table specifically because they are too dark or give you a headache, check out Blue Shark Optics. They are made specifically for poker, and they have many different styles to choose from.