Blue light is part of natural light. In the winter we don't get enough which is part of seasonal affective disorder and it is what helps with light box therapy. In the summer we can get too much and get manic from it. Amber glass therapy can help with that. Blue light also comes off televisions and computer screens so those can be activating, messing up sleep patterns. I use a program called f.lux to decrease blue light on my computer at night.

You can read more about this by searching on the link I gave above.

Some people find light restriction can really be effective and stick to it really intently; others find it somewhat helpful.