You learn something new every now and then.

I can't recall exactly when was the first time I started aiming my desk lamp behind my 23-inch PC monitor at home, but unconsciously, I find that adding a bit of back-light, soothing. Especially when playing games in my pitch-dark room.

Well, apparently, this corona-like glow has a name: >Bias Lighting<

When we watch television or use a computer work station in a completely dark or significantly darkened room we create a less-than-ideal viewing situation wherein our eyes are staring very intently at a small window of very bright light that is floating in a sea of darkness. Despite the fact that we accurately perceive the screen to be very bright in relationship to the rest of the scene our eyes take in, our eyes attempt to adjust based on the average brightness across the entire field of view and not the average brightness of the screen (or, conversely, the dimmer off-screen area). As a result our eyes become rapidly fatigued and with extended exposure we experience dry eyes, general discomfort, watery eyes, and even tension headaches radiating out from the temple area. In worst case scenarios with extended exposure some people experience ocular migraines, extreme headaches that result from intense eye strain.