From Compendium of Worldly Lore
Needs review
Source: Player's Handbook II
Description: You learn to sense a foe's presence even with your eyes closed.
Prerequisites: Blind-Fight, Base Attack Bonus +12, Combat Focus
When you maintain your combat focus, you have an uncanny ability to sense the ebb and flow of your opponents' vitality. As you attain greater mastery of this fighting style, you learn to sense a foe's presence even with your eyes closed.
While maintaining your combat focus, you learn the current hit point total of each adjacent opponent and ally. If you have three or more combat form (Combat Defense, Combat Focus, Combat Stability, Combat Vigor) feats, you gain blindsight out to 5 feet.
Special
A fighter can select Combat Awareness as one of his fighter bonus feats.