Needs review
Source: Oriental Adventures

Description: You have mastered the art of striking a nerve that blinds a humanoid opponent.

Prerequisites: Base Attack Bonus +4, Improved Unarmed Strike, Stunning Fist, WIS 17

Against a humanoid opponent, you can make an unarmed attack that has a chance of blinding your target. If your attack is successful, your target must attempt a Fortitude saving throw (DC 10 + 1/2 your level + your Wisdom modifier). If the target fails this saving throw, he is blinded for 1 round per level you possess. In addition to the obvious effects, a blinded creature suffers a 50% miss chance in combat (all opponents have full concealment), loses any Dexterity bonus to AC, grants a +2 bonus on attackers' attack rolls (they are effectively invisible), moves at half speed, and suffers a —4 penalty on most Strength- and Dexterity-based skills.

Using this feat uses up one of your stunning attacks for the day (either a monk stunning attack or a use of the Stunning Fist feat).