Three Types of Light Therapy
Health news regarding light is usually relegated to one of two categories: vitamin D or skin cancer. But what many don’t realize is there’s a whole world of uses for light in health, ranging from mental health to dermatology. We asked three experts in the field to break down the major types of light therapy.
Dr. Elizabeth Buzney, an associate physician and instructor in dermatology at Brigham and Women’s Hospital, defines phototherapy as using ultraviolet light to reduce inflammation in the skin. The therapy is most commonly used to treat psoriasis, but it can also help combat eczema, cutaneous t-cell lymphoma, generalized itch, and, occasionally, hives.
“We use, for the most part, a lightsource called narrow band UVB,” Buzney explains. “What that is, is a particular wave length [311 to 313 nanometers] within the UVB spectrum which has been isolated specifically for psoriasis to help reduce inflammation in the skin.”
Buzney admits that experts themselves aren’t sure exactly how light works to treat skin conditions—the theory is that it has to do with the immune cells in the skin—but they do know that it can safely decrease inflammation.
Buzney is quick to differentiate the treatment from other UV-light apparatuses like tanning beds. “When you walk into a tanning bad, you’re primarily getting UVA radiation with some UVB as well,” Buzney says. “Every tanning bed has a different combination of UVA and UVB that they’re using, whereas we have chosen a very specific set of wave lengths which we know target inflammation without causing the tanning and the skin cancer.” In the 25 years narrow band UVB has been around, Buzney says, no studies have shown a link between it and increased risk of skin cancer.
Phototherapy is a good option, Buzney says, because it is a mid-range treatment—not as intense as immunosuppressant drugs, but more successful than topical steroids or other creams. Plus, she notes, its a relatively risk-free and affordable option, though patients do have to come in as often as two or three times a week.
“Phototherapy has no internal side effects. The biggest risk with phototherapy is a risk of burn, and that is something that we try our best to avoid with a number of different safety practices in place,” Buzney says. “It’s safe for older people, it’s safe for pregnant women. It’s safe, it’s effective, you don’t have to do lab tests, there’s no risk of serious complications.”
Ever get depressed when fall turns to winter? You’re not alone. About 25 percent of the population at our latitude will experience some kind of seasonal depression, and light therapy can provide some relief, says Brigham and Women’s psychologist Dr. Janis Anderson. “One of the ways [sufferers] can counteract it is to provide their brain, their body, with a signal that’s consistent with a summertime signal in the sense of when light is available,” she says. “[Light therapy] is using some kind of a device to create light that you can shine on the area around your eyes so that it kind of supplements light exposure you might otherwise get from being outdoors.”
After three or four sessions, Anderson says that patients usually start to see results from light therapy, and the bulbs can be purchased and used in the home. Even spending more time outside is helpful, she says, thought it’s not always practical for people with nine-to-five jobs.
Anderson, like Buzney, says the mechanism by which light therapy works is not fully understood, but says it likely stems from the body’s natural cyclical regulation. “In the modern era, it might seem kind of strange that your body would change its metabolic activity in January versus July,” Anderson says, “but if we were not living under modern conditions and had to be outdoors a lot and interacting with the temperatures and so forth, then it would be very helpful to have our body automatically readjusting itself.”
“You don’t think of laser as being light, but that’s exactly what it is,” Buzney says. “[It’s] often used for cosmetic reasons. Laser uses visible light, and, depending on which wave length you target, can eliminate red spots or brown spots, take care of veins, or even do resurfacing of your skin.”
But laser therapy doesn’t stop at minor cosmetic procedures. Dr. Virginia Litle, a thoracic surgeon at Boston Medical Center, says laser therapy of a different sort, called photodynamic therapy, can be a useful tool for treating cancer.
“What it involves is injecting a patient intravenously with a photosynthesizing agent,” Litle says. “After a patient’s injected with it, the cancer cells take it up. Then, to kill the tumor cells, a non-thermal laser [is used].”
Though Litle says the therapy can be very successful “at obliterating tumors,” she notes that it is extremely expensive, not widely available, carries a relatively high risk of side effects, and is increasingly being replaced by other therapies. “I would recommend it, again, if somebody had a bulking tumor, or a bleeding tumor,” she says. “I think a lot of it’s for historical interest, but there are still some [uses].”