As Players noted, Blinding for 1d6 Melees in combat is a death sentence in most cases. I changed it to Blinding Flash and it now has this description:
Attacking a person with this invocation causes them to go blind for 1 Melee. Bonus MP can add +1 Mystic Attack Level / 2 MP, and/or +1 Duration / 2 MP and/or +10' Range / 1 MP.