For some, there are threats everywhere. They fear the world is dangerous and, unless they stay in a constant state of vigilance, their lives will be at risk. In a small number of cases, this gets out of control and tips into paranoia and mental disorder. For the majority, it’s an exaggerated caution because they do not understand how modern technology works. They see how dangerous electricity can be and so are cautious when using powered equipment, particularly when that involves the use of "radiation". Now there’s a word to get the conspiracy theorists into action. Yet, from a scientific point of view, you cannot escape the fact that television and computer screens give off electromagnetic radiation (EMR), handphones rely on microwave broadcasts, and then there’s light. In coherent form as a laser, it can potentially blind people. As it shines from the sun, we can see our way and, with appropriate protection from ultraviolet, live healthy lives.

The white light we "see" is in fact made up of all the colors blended together. Each color has a property of its own and you may have seen increasing publicity given to light as a treatment for skin problems like acne. When it’s projected from a TV or computer screen, you get both the EMR and light in the visible spectrum, often with a slightly bluish tinge. For the treatment of skin problems, blue and red are used. For the treatment of sleep disorders, blue and green are being used in a series of clinical trials. It’s perhaps slightly ironic, but those who felt an effect from television and computer screens were probably right, except that the effect seems to be beneficial if you want to change your sleeping times.

We know when to sleep because our internal clock is set to match the local daily cycle. If we move to different time zones so that morning is now night, this confuses us and we find it difficult to match local time for sleep. As a trial, a number of people were cut off from the world in rooms without windows or clocks. There was no way for them to tell how much time was passing. The research team kept them awake for fifty hours and then allowed sleep for eight. When awake, half were exposed to blue light, the other to green. All the participants were carefully monitored and it was found that both colors could reset the internal clocks. The only difference between the two groups was that dim blue and bright green lights were less effective. The relevant neurotransmitters and hormones responded more precisely to bright blue and dim green.

So, in all situations where the sleep problem is caused by the body’s circadian rhythms not being properly synchronised to local time, the use of light may well prove the best long-term solution. Although a drug like ambien can and does produce sleep "on demand", there are always problems if you come to depend on a drug for any long-term solution. Ambien will always help you get needed rest, but the use of alternative methods is preferable. As counseling and therapy is expensive and often not covered by health insurance plans, the development of light treatment may come as a simple and cheap solution to sleep problems.