By Rajnish Mago, MD (bio)
Bright light therapy is an important treatment modality in mental health but is underutilized. To help clinicians with using bright light therapy appropriately, on other pages on this website, we have discussed exactly how bright light therapy should be done (see Related Pages below).
A key question is—which bright light therapy devices meet the criteria for being both efficacious and safe? As of November 2019, the United States Food and Drug Administration (FDA) does not regulate bright light therapy devices and none has been cleared by the FDA. But, a study published in November 2019 systematically evaluated 24 bright light therapy devices (Oldham et al., 2019).
Criteria for adequate bright light therapy devices
What are the criteria for bright light therapy devices that are efficacious and safe and may be recommended to our patients? The authors established three main clinical criteria for what they would consider to be an adequate bright light therapy device:
1. Did the device produce light of at least 7000 lux intensity at 12 inches or the manufacturer-recommended distance (if more than 12 inches)? They used a cut off of 7000 lux as the minimum intensity instead of 10,000 lux because of some research that suggested that 7000 lux may be adequate. I am not sure that I agree with this. The studies they cite were done in vulnerable populations (bipolar depression, antepartum depression) and a lower intensity may have been justified in those patients. But, unless future research clearly shows that less than 10,000 lux is efficacious for major depressive episodes, we should stick to recommending devices that deliver 10,000 lux of bright light. We should also keep in mind that when a device is said to deliver light of 10,000 lux intensity, that is under the best-case scenario—the patient is sitting close enough and the patient is not moving much from side to side. Which brings us to the second criterion that these authors used…
2. Was the field of illumination large enough so that the user could move a bit and still get enough bright light? The size of the minimum required field was specified. I have been concerned about clinicians and patients considering small bright light therapy units. We should realize that unless the patient is willing to sit still for the duration of bright light therapy treatment, a large enough field of illumination is essential.
3. Was the intensity of the glare from the device at or below an acceptable level that had been determined by testing in their subjects?
Besides the three clinical criteria listed above, there are some more that a bright light therapy device should meet for us to recommend it to our patients.
1. Type of light
Several bright light therapy devices are now available that use LED light or blue light. I will discuss these on other pages on this website. But, as I recommended on another page on this website, for now, let’s stick to the best-studied and well-proven type of light—fluorescent white light.
2. Efficacy ratio
Using a formula suggested by a previous study (Baczynska and Price, 2013), for each device, the authors calculated an “efficacy ratio” (Oldham et al., 2019). In simple terms, this is the ratio of the light intensity associated with postulated therapeutic efficacy to the apparent brightness. Obviously, it would be good to have light of a type that provides more efficacy without appearing to be excessively bright.
1. Diffusion screen
The authors also required that an adequate device would also have a diffusion screen that prevents hot spots of extra intensity that could expose parts of the retina to unduly intense light (Oldham et al., 2019).
2. Ultraviolet light protection
I tell my patients that just as it is not a good idea to buy cheap sunglasses that may not have good protection against ultraviolet (UV) light, it is also not a good idea to buy a bright light therapy device that does not have 100% ultraviolet light protection.
3. Protection ratio
Light in the blue wavelengths is more toxic to the retina compared to light in other wavelengths. So, the others calculated a “protection ratio,” which, in simple terms, is the ratio between the light intensity associated with therapeutic efficacy and
the estimated retinal risk based on the blue light hazard.
Adequate bright light therapy devices
Of the 24 devices tested, only 7 clearly met their criteria for adequate bright light therapy devices (Oldham et al., 2019). These included 4 large light boxes and 3 smaller light boxes.
In addition to these seven light boxes, 5 other bright light therapy devices that are not light boxes had properties whose efficacy is supported by some limited research. These types of devices, including LED beam units and visor devices, will be discussed on other pages on this website.
On this page, I’ll list all the 7 light boxes (4 large and 3 smaller) that were judged to be adequate. You will note the huge differences in price between these devices. But, on another page on this website, I’ll explain why the price is only one consideration and we should not automatically recommend the cheapest of these devices.
Large light boxes
Four large light boxes that easily exceeded the criteria for adequate bright light therapy devices (Oldham et al., 2019). But one of these four devices is not being marketed at this time, leaving us with three that met their criteria.
1. Day-Light Classic (Model DL930; Carex Health Brands). $99.
Available on Amazon.com at this link: Day-Light Classic Bright Light Therapy Lamp>
The more expensive, larger sized (“plus”) version of this device ($115) is available on Amazon.com at this link: Day-Light Classic Plus Bright Light Therapy Lamp
2. NorthStar 10,000 (Alaska Northern Lights). $299
Not available on Amazon.com as of November 2019. Available at this link: http://www.alaskanorthernlights.com
3. SunRay II (The SunBox Company). $369.
Not available on Amazon.com as of November 2019. Available at this link: https://www.sunbox.com/shop/10000-lux-bright-lights/sunray-ii/
Smaller light boxes
Three smaller light boxes that minimally met the criteria for adequate devices.
Again, I will review and compare these devices in detail on another page on this website.
1. Day-Light Sky (DL2000; Carex Health Brands). $112
Available on Amazon.com at this link: Carex Day-Light Sky Bright Light Therapy Lamp
2. BOXelite (Northern Light Technologies, Inc.). $182
Available on Amazon.com at this link: Boxelite 10,000 Lux Bright Light Therapy Light Box, Black
A related, more expensive device ($208) is available on Amazon.com at this link: Boxelite-OS 10,000 Lux Bright Light Therapy Light Box, Black)
3. SunTouch Plus (Nature Bright Company). $61
Available on Amazon.com at this link: Nature Bright SunTouch Plus
For a comparison of these bright light therapy devices and how to choose between them, please see this article:
Disclosure: The links above to Amazon.com are affiliate links. Amazon.com offers websites that link to any product sold by them a small commission at no extra cost to the customer.
Oldham MA, Oldham MB, Desan PH. Commercially Available Phototherapy Devices for Treatment of Depression: Physical Characteristics of Emitted Light. Psych Res Clin Pract 2019;1(2):49-57. Available at https://prcp.psychiatryonline.org/doi/full/10.1176/appi.prcp.2019.20180011
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