Cause / Cure Blindness Spell

The target suffers complete and permanent blindness, as if by a stroke.  The same spell can reverse blindness if the eyes and optic nerves are essentially intact.  The spell costs 8 magic points for either version, and an additional 2D6 sanity points for Cause Blindness. A day of rituals and successful POW vs POW match on the resistance table are also needed.