White, Blue, Green? Which light is best?

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by Marsha Stopa

This is the sixth article in the Bright Light series.

If you’re confused about the differences between bright white light therapy, blue LED light and low-intensity green light therapy, you’re in the right place. Give me a minute.

Lots of research into light therapy

That’s good news. Researchers are learning more all the time about using light therapy to treat non-seasonal depression, bipolar disorder and depression in teens. It’s encouraging and exciting. It also makes it more confusing to sort through the recommendations.

If you take the time to read through all the research articles linked from the light box manufacturers’ websites, (good sources, by the way) you’ll find medical experts who support each kind of light therapy and medical experts in opposition. So, who’s right?

Some, not all the answers

The oversimplified answer: They all are. To some degree.

The ultimate, unanswered question in all of this research comes down to whether there is long-term risk and eye damage from the different kinds of light therapy. The bright light supporters say they have the most evidence from 25 years of research that bright white light is not a risk.

The blue LED light supporters say the shorter, blue wavelengths are more effective and not a risk. The green light advocates say everyone else is wrong and only low-intensity green light is the safest and most effective.

At this point, I have used all but green light over the past 10 years of light therapy. I started with standard, bright white light therapy and it was effective, although I had to periodically increase my treatment time. I used a blue LED light for about four years and it also was effective, but I also needed increase my treatment time periodically.

I’m currently using the Litebook Elite white LED and it is effective in 15 minutes, and I also had to increase treatment times during long, dark stretches of this past winter. (Disclaimer: Litebook sent me its product to review.)

Consider your risk

As I’ve written in previous posts, the way you will use the light and the amount of time you have to use it are considerations in your purchase. Your risk level is another consideration. I have healthy eyes that show no change after nearly 10 years of light therapy, about four of those years with a blue light, although recent research indicating that blue-light causes long-term retinal damage has me concerned.

I was initially more open to using blue light, but I’ve changed my mind and switched back to white light. If you have an eye condition, eye disease or think you may be at more risk for developing macular degeneration, you should definitely avoid blue light. Let me be more clear: Don’t buy a blue light.

Consider using a lower-intensity white light, increasing the distance from your face, or raising the overall level of background light in your home or environment. Talk to your ophthalmologist.

If you’re attracted to the smaller size of the blue LED lights and the average, 15-minute treatment time consider the white LED Litebook. Larry Pederson, founder of The Litebook Ltd., and a Canadian SAD sufferer, told me that his product combines the effect of blue light and green light into white light, bright enough to effectively close down the iris just enough to achieve the beneficial effect but avoiding retinal damage.

Don’t stare into the light

If none of this discussion convinces you, seek a second opinion. I turned to one of the most respected medical institutions, The Mayo Clinic, for its advice on light therapy.  I quote: “To help reduce this risk, don’t look directly at the light source in any light therapy box. Check with the manufacturer if you have concerns about a light box’s safety.”

Simple enough. We don’t stare directly into the sun; we shouldn’t stare directly into any light therapy box, either.

If this article helped you, you’ll find more help in the rest of the Bright Light series:

Don’t leave without getting the Light Therapy Lamp Guide to help you shop by brand. It will save you hours of research. It comes with the winter guide, Your 8 Step Plan to Stopping the Winter Blues, a 37-page ebook that lays out the pieces of the winter blues puzzle and solves the mystery.

Let me know how I can support you.

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{ 6 comments… read them below or add one }

1 pharmacy tech February 7, 2010

What a great resource!

2 brian October 15, 2012

350 lux of green light is as effective as 10,000 lux of white light therapy. http://en.wikipedia.org/wiki/Seasonal_affective_disorder#Treatment

I always wondered why green light therapy isn’t so popular when it’s safer for the eyes and requires fewer lux. There aren’t that many reviews either. It would be cheaper to make your own.

3 binotto December 2, 2012

Hi Marsha,

Thanks very much for this article. I’m in the process of choosing a light box and all of the different claims are quite confusing. I’ve just found an article (linked from the Litebook website) that describes a controlled trial of the Litebook (http://www.biomedcentral.com/1471-244X/7/38/). It says that the light has a major peak at 464nm (blue) and a secondary peak at 564nm (green). The goLITE blue colour is 469nm. There is a new study from Harvard (http://www.translationalmedicine.org/content/2/31/31ra33.short) that suggests that using blue and green light together might give better results than just blue light. It looks like this is what the Litebook is trying to achieve.

4 Marsha Stopa December 2, 2012

Thanks for the link to the Harvard study.

I am very wary of all-blue light boxes as some research has shown all-blue light to be a factor in retinal damage over the long term. I’m very curious to take a look.

Thanks again.


5 Brian March 23, 2013

I’ve heard about blue light being more effective than other colors.
Too much blue light may be harmful but 10,000 lux white light produces more blue light than a blue light box. Adding unnecessary wavelengths may also cancel out the effectiveness of blue light. You can eat lutein rich foods to make your macula blue blocking.

6 Marsha Stopa March 25, 2013

More effective, yes. Safe, still debatable.

A white lightbox may produce more blue light but it is also brighter than all-blue lightboxes, thereby closing down your retina more and helping prevent damage. At least that’s the theory.

Thanks for these links so we can all continue to educate ourselves.

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