Recently a press release crossed my desk advertising a blue light application for your iPhone (now) and for the Blackberry and Palm soon. I was amazed at the brash medical claims this software maker was claiming — claims that one might think might need to evaluated by the Food and Drug Administration because they relate to the claimed treatment of seasonal depression.
What’s so special about blue light?
In recent years, there’s been a growing body of research that suggests light in the 460 – 470 nm wavelength spectrum can be particularly effective in helping people with seasonal affective disorder (also called seasonal depression or SAD). It’s also been theorized to help fight fatigue and drowsy driving.
But here’s the rub. When you examine those studies, you find that it’s not only the wavelength that’s important, but also how much of the light you’re getting (e.g., what’s the lux output of the light device). In the research, the lux ratings of the devices used range from 398 lux to 1,350 lux for at least 30 minutes per day (and in some cases, much longer).
The new software application from the press release is available only for cell phones. Guess what the lux output on cell phones is? According to tests conducted by WirelessInfo.com:
- Apple iPhone 3GS – 133
- Apple iPhone 3G – 207
- Apple iPhone – 168
- Blackberry 8800 – 90
- Helio Ocean – 63
- LG Prada – 43
- Nokia N95 – 72
- Palm Treo 750 – 60
So assuming you’re using the latest iPhone 3 GS, you might need to sit in front of the application, close to your face, for up to 3 times as long to get the same benefits that clinical studies have shown. There have been no clinical studies that I could find that used such low lux output blue light.
In contrast, the the press release trumpets:
In just 15 to 30 minutes a day, this application invigorates your mind and body as well as expensive light boxes.
In the actual research, the minimal amount of time in front of such devices was 18 minutes — with light output that was more than twice as bright as an iPhone. Most studies done on blue light required the participants to get between 30 and 45 minutes of exposure, every day. Participants were sitting 1 to 2 feet away from the light source in this research.
So you’d think they’ve done their own clinical studies to actually examine a cell phone’s effectiveness using this software. On the “Clinical Studies” link on their website, they link to such rigorous journals as CNN Health, and Modern Medicine. None of the links demonstrate the use of this particular software, but are instead about the potential uses and benefits of clinically-tested blue light therapies. The one study that comes close to providing evidence for their software was never published in a peer-reviewed journal (it’s a “white paper,” meaning its methodologies were never subjected to professional scrutiny).
Without apparently any original research of their own, their CEO makes the following claims about their software:
The light is effective when placed anywhere within four feet of your face at any angle. You can lean it up on a phone stand or lay it on your desk or kitchen table. It’s also highly effective for long road trips and night driving without interfering with the driver’s vision. This application is also great for college students who need to focus for late night study sessions.
It is highly dubious that anything this guy is saying is based upon research conducted using the software he is actually selling.
Blue light in the 460 to 470 nm spectrum does indeed show strong clinical evidence that it can be effective in helping treat seasonal affective disorder. But it’s probably a stretch to say that you can replicate these clinical results on low lux devices like cell phones. Unless, perhaps, you have the phone within a foot or two of your face, and you stare into it for 45 minutes a day.
7 comments
You cannot measure Blue light in Lux.
This can only be measured in photons per square cm.
Blue light is actually 5 times more effective than full spectrum light is alleviating symptoms of SAD
Wait, but if the blue light thing is true, would that mean that for the average office worker, who spends 6+ hours in front of an lcd monitor, be able to help combat their SAD symptoms by making the majority of the screen blue?
Thanks for debunking these claims.
Opthamalogical studies conclude that blue light causes damage to your eyes over time, and light therapy boxes warn against looking straight into the lamp.
Although I haven’t read anything specific to cell phones, artificial blue light at night disrupts circadian rhythms and can contribute to insomnia, can trigger episodes in bipolar disorder, and some studies show an increased cancer risk. Blue (and green) light is a zeitgeber, or time disturbance, that messes with chronobiology.
(Blue light therapy for seasonal affective disorder is used during the day, as a supplement to natural light, in order to stimulate natural circadian rhythms – exposure to blue light at night does the opposite.)
Hank Roberts & myself have compiled a huge amount of information about these risks, here:
http://psychcentral.com/blog/archives/2007/03/12/light-and-dark/
I just wanted to let everyone know about a free, abundant, and powerful source of blue light that I have known about for a long time. It’s called THE SKY. Looking up at a clear blue sky feels great and it doesn’t cost a thing, but you have to get out of your office every once in a while and take a walk in the sunshine.
Unfortunately, the sky is not always clear and blue, but there is a way to gain some of the physiological benefits of sunlight without resorting to expensive light therapy machines (or cheap, ineffective iPhone applications): supplementation with Vitamin D.
Anyone with an interest in Seasonal Affective Disorder should read through the extensive studies on SAD and vitamin D, including:
Vitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder
http://www.ncbi.nlm.nih.gov/pubmed/10888476
There are some studies that found no connection between Vitamin D and SAD. There are also search parties that don’t find a missing person. It doesn’t mean the person no longer exists. The sun causes your body to make vitamin D, and people get SAD when sunlight decreases. Could it be any more obvious?
More interesting research abstracts are available here:
http://www.ncbi.nlm.nih.gov/sites/entrez
Just search for:
seasonal affective disorder vitamin d
Rachel,
From what I understand, Serotonin levels play a large part in Seasonal Depression. I would think to a greater extent than Vitamin D. Serotonin levels increase with UVA light from the sun. While Vitamin D might interact with Serotonin at some level, the most up-to-date biochem book I have does not list Serotonin stimulation as one of Vitamin Ds functiosn.
if you are going to occasionally update this, at least update to current phones so it stays relevant. The phones used in your paper are were released over 10 years ago. You would be hard pressed to find a working phone in this this.