Blue light waves are emitted from TVs, computer screens and some light bulbs including some fluorescent and the high efficiency light bulbs. Turns out that blue light is alerting and more than that, it can limit or prevent melatonin production in the evening when we need melatonin for our sleep cycle. After seeing blue light, it can take up to 90 minutes for the alerting effects to subside and melatonin production to kick in. During this time, you may have a very antsy child happy as a clam, dancing on his bed.
This problem can be avoided by limiting TV and computer in the evening. A child who is very sensitive to light may also benefit from wearing blue-light glasses at night 1-3 hours before bedtime. The glasses are orange and do not allow blue light waves to penetrate. There is evidence for the glasses working in adults. There is anecdotal evidence for children - but I haven't seen a formal study.
Another option is to install yellow light bulbs. They come in a variety of forms including the new energy-efficient cork-screw style bulbs, and can be purchased on-line. Stay posted - I'm going to buy one for the hallway outside my bedroom to see how well the yellow lights work in general.
Here is a web site to check out: LowBlueLights.com. They offer junior sizes of glasses and the yellow bulbs.