Blackout is a unique screen-dimming and focus aide which helps you concentrate on your work - while saving your eyesight. Blackout provides instant screen dimming without affecting your hardware or gamma settings.
Blackout also provides unique 'Spotlight' and 'Soft Edges' modes: use the Spotlight mode to have a circle of light follow your cursor, or stay fixed on an important area of your screen. Use the Soft Edges mode to subtly dim the corners of your Mac's monitor, helping you stay concentrated on what counts
ST8181 have been using daily (or nightly, rather) since 3.1, the new dual display support added in 3.3 is even better since i just got a second cinema display. i am now using Blackout's "Soft Edges" effect on my main display and a cursor-following spotlight on my second. can't imagine working at night without this app now. 5 stars (Version 3.3)