A simple test of Gunnar v.s. Gammar Ray computer glasses with a blue light laser (~405nm) shining through the lenses. Actual test starts at around 2:20
Tested with Gunnar Intercept Onyx (about $65 dollars) and Gamma Ray "Stealth Mode" Flexlite computer glasses (about $25 dollars).
Results show that Gunnar lenses do block more blue light more than the Gamma Ray lenses, however it is inconclusive whether it is significant enough to justify wearing more expensive and less comfortable frames. Comfort is important too.
However, see the Gunnar website for some additional features of Gunnar lenses that may be worth noting. Supposedly the lens is curved in such a way that prevents eyes from drying, so that might be important for some.
Personally, I plan on returning the Gunnar's, keeping the Gamma Ray's for my wife who spends considerably less time in front of the computer, and purchasing a new pair of Gunnar's for myself that have a different frame style.
Now that I have confirmed that the Gamma Rays actually *do* block some blue light, and are more comfortable, it makes sense to keep them around.
I hope this helps somebody, even though I don't have a clear conclusion from all of this.