A great, inexpensive gift for that guy that has everything, and loves his TV.
Bias lighting (or sometimes ambient lighting) is simply a strip of little lights you apply to the back of your flat screen, especially if it is close to the wall, and even more especially if you often watch it in the dark.
The strip functions to reduce eye strain in the following ways:
1) Focus - your eyes are focusing on the video/TV, but they're biologically oriented to also focus on the wall, and try to measure that depth. So that delta can actually tire your eyes.
2) Strain - the shift from light picture to dark and back to light can cause strain, and having ambient light around back of the TV helps reduce the struggle with that contrast.
3) Richness of Blacks and Grays are also improved
This guy does a good job of showing how to install a bias lighting LED strip. Helpful.