Understanding a light box
A light therapy box mimics outdoor light. Researchers believe this type of light causes a chemical change in the brain that lifts your mood and eases other symptoms of SAD.
Generally, the light box should:
- Provide an exposure to 10,000 lux of light
- Emit as little UV light as possible
Typical recommendations include using the light box:
- Within the first hour of waking up in the morning
- For about 20 to 30 minutes
- At a distance of about 16 to 24 inches (41 to 61 centimeters) from the face
- With eyes open, but not looking directly at the light
Light boxes are designed to be safe and effective, but they aren't approved or regulated by the Food and Drug Administration (FDA) for SAD treatment, so it's important to understand your options.
You can buy a light box without a prescription. Your doctor may recommend a specific light box, but most health insurance plans do not cover the cost.
What to consider
Here are some questions to think about when buying a light box for seasonal affective disorder:
- Is it made specifically to treat SAD? If not, it may not help your depression. Some light therapy lamps are designed for skin disorders — not for SAD. Lamps used for skin disorders primarily emit ultraviolet (UV) light and could damage your eyes if used incorrectly. Light boxes used to treat SAD should filter out most or all UV light.
- How bright is it? Light boxes produce different intensities of light. Brighter boxes will require less time to use each day, compared with dimmer boxes, to achieve the same effect. Typically the recommended intensity of light is 10,000 lux.
- How much UV light does it release? Light boxes for SAD should be designed to filter out most or all UV light. Contact the manufacturer for safety information if you have questions.
- Can it cause eye damage? Some light boxes include features designed to protect the eyes. Make sure the light box filters out most or all UV light to avoid damaging your eyes. Ask your eye doctor for advice on choosing a light box if you have eye problems such as glaucoma, cataracts or eye damage from diabetes.
- Is it the style you need? Light boxes come in different shapes and sizes, with varied features. Some look like upright lamps, while others are small and rectangular. The effectiveness of a light box depends on daily use, so buy one that's convenient for you.
- Can you put it in the right location? Think about where you'll want to place your light box and what you might do during its use, such as reading. Check the manufacturer's instructions, so you receive the right amount of light at the proper distance.
Talk to your health care professional about light box options and recommendations, so you get one that's best suited to your needs.
March 16, 2016
See more In-depth
- AskMayoExpert. Seasonal affective disorder (SAD). Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2015.
- Martensson B, et al. Bright white light therapy in depression: A critical review of the evidence. Journal of Affective Disorders. 2015;182:1.
- Sanassi LA. Seasonal affective disorder: Is there light at the end of the tunnel? JAAPA. 2014;27:18.
- Avery D. Seasonal affective disorder: Treatment. http://www.uptodate.com/home. Accessed Feb. 8, 2016.
- Melrose S. Seasonal affective disorder: An overview of assessment and treatment approaches. Depression Research and Treatment. 2015;2015:1. http://www.hindawi.com/journals/drt/2015/178564/. Accessed Feb. 8, 2016.
- Kurlansik SL, et al. Seasonal affective disorder. American Family Physician. 2012;86:1037.
- Hall-Flavin DK (expert opinion). Mayo Clinic, Rochester, Minn. Feb. 15, 2016.