As recently highlighted in a CGFL league meeting and we have stressed for many years now.
Players can only wear sports glasses with a wrap-around design. If for example, the glasses have any type of normal hinged design they are not allowed to be worn by players.

 If a player is wearing glasses, the referee should check that they are sports glasses, which do not contain glass or a metal frame.

This is for the safety of the player and other participants.

Any player wanting to wear glasses which the referee deems to compromise safety should remove the glasses or not be allowed to play until so.

Please see the Laws of the Game here which will help you with any decisions.

We also advise that this also applies to training sessions as well as matches.