Blind

Blind creatures automatically fail all tests based on vision, and automatically fail all Ballistic Skill tests.
Such creatures take a –30 penalty to Weapon Skill tests and most other tests that ordinarily involve or are benefited by vision. Note that this trait indicates not only that the creature cannot see but that it also has no other senses which would provide the same benefit as eyes (such as Unnatural Senses). The Blind Fighting talent reduces the penalty to Weapon Skill tests as normal for Blind creatures, from –30 to –15.
Dark Heresy - Core Rulebook - 134