Effects:
Requires the target to make a perceive check to hit, move, or defend and decreases the target's perceive by 5. Difficulty of perceive checks increased by 1 level. If the target fails their perceive check when moving, the target will fall down. Depending on the cause of blindness, it could become permanent - such will depend upon the situation and GM. If blindness does become permanent, it is possible to develop other senses to remove the perceive penalty, and even maybe add bonuses to it, however perceive checks will become a fact of life.
Sample Cures:
time for effect to wear off