Stolen from Wiki:
In February,1979, Parent's career was cut short by a career ending eye injury in a game against the New York Rangers. An errant stick entered the right eye hole of his mask causing permanent damage to his vision. This incident led many NHL goalies to move away from the fibreglass facemask toward the cage and helmet style widely used today.
Parent was awesome. Lights out when he was on his game, which was most of the time.