As Mike Q has posted, per RAW Dirty Trick cannot create a permanent effect.
However, if the character is high enough level to take the Blinding Critical feat, what you can do is to let them treat the glass as a reskinned shuriken, or as many shuriken as the character can throw in one round. If they want to improve their chances of success, they can then take the relevant throwing/crit feats.
A strict GM might treat this as an improvised weapon, but since it's not actually conferring an advantage over buying regular shuriken, it'd be fine to overlook that issue in the interests of flavour.
IRL, there are plenty of ways to permanently blind somebody in melee combat. A blow to the back of the head can cause retinal detachment or occipital lobe injury; being stabbed or shot in the face can also do it. You can even do it in grappling. And, yes, glass dust or sand in the eye could do it in the long term (not immediately, but through corneal scratching, infection, and scarring after the fight is over).
But Pathfinder isn't that simulationist of a game. Most weapon attacks just do hit points; to cause permanent impairment you need something like Blinding Critical, and the prereqs for those feats are set quite high. If a 14th-level character can't blind somebody by stabbing them in the eye with a dagger, then a much-lower-level character probably shouldn't have the option to do so with what's essentially an improvised weapon.