|The following is based on Fallout: New Vegas cut content and has not been confirmed by canon sources.|
Focus only exists as a Pip-Boy 3000 icon image, found in the game files, depicted as an eyedropper bottle with "FOCUS" written on it.
Behind the scenesEdit
According to Joshua Sawyer, Focus' effect would've been to decrease the field of view slightly, and even more so when aiming down sights, allowing for larger visual profiles of distant enemies. The effect, however, did not work when using scoped weapons.