Light Therapy: Treatment, Effects & Risks

Light therapy has been used in Germany since as early as 1987. Since then, it has become the preferred form of therapy for sleep disorders, seasonal depression, as well as disorders of the so-called internal clock. Light therapy is also used in the private sector as an easy-to-use remedy for winter depression, headaches, migraines and for acne.

What is light therapy?

This physical therapy method is used especially for psychological ailments and skin diseases. The method of light therapy, which is recognized by scientific medicine, is used to treat various diseases in human medicine. This physical therapy method is used especially for mental ailments and skin diseases. Depending on the treated disease, different radiation parts of light are used. Phototherapy is a special form of light therapy. In this, only short-wave blue light in a wave range of 450 to 460 nm is used.

Function, effect, and goals

Light therapy achieves particular success in the treatment of depression. Particularly in the case of seasonal depression, which regularly occurs during the dark season of the year, targeted light therapy helps to lower the melatonin level in the brain and stimulate it to release more serotonin. This messenger substance has been proven to combat depression and is contained as an active ingredient in many antidepressants. For this application, a bright, fluorescent lamp with a full light spectrum and 2500 to 10,000 lux luminous intensity is used, which shines about 200 times brighter than usual room lighting. Since the necessary effect of light is probably mediated solely through the eyes, the best results are obtained when the light source for light therapy is placed about 90 cm from the face. Migraine attacks can also be reduced in the long term with regular light therapy, as these are also partly triggered by a serotonin deficiency, which can be compensated for by regular treatment with light. Light therapy is recommended for migraine patients in the early morning, as the pain usually starts in the morning. Another field of application of light therapy is the treatment of neurodermatitis. Here, the affected areas of the body are irradiated with UV light. In the case of chronic skin changes caused by neurodermatitis, UVB therapy is primarily used, which has a relatively positive effect but relatively few side effects. In acute attacks of severe neurodermatitis, UVA1 therapy is used. The dosage for this light therapy ranges from low to high, depending on the severity of the flare. However, since the heat of the UVA light can intensify the itching, the infrared part is filtered out and only the so-called cold light is used. In PUVA therapy, irradiation with UVA light is supported by taking tablets that are supposed to increase the body’s sensitivity to light. Mixed irradiation with UVA and UVB light is also carried out as part of light therapy for neurodermatitis. Suitable light therapy can significantly improve the skin condition in acne vulgaris (common acne). The prerequisite for success is the correct wavelength of light. The antibacterial effect of blue light eliminates the cause of inflammation within the skin pore. Light therapy with red light in a wavelength range of 580 to 659 nm helps heal wounds due to its relaxing and circulation-enhancing effect.

Risks and dangers

There are no known serious side effects associated with full-spectrum light therapy, but the effects of antidepressants or antipsychotics may be enhanced, and the medications used in PUVA therapy often have undesirable side effects such as sun sensitivity and nausea. In rare cases, patients complain of burning eyes, headaches, irritability, dry mucous membranes, and skin redness. Certain medications such as antibiotics, lithium, St. John’s wort, diuretics and medicinal skin ointments can make the eyes more sensitive to (UV) light. Therefore, if taking such medications, a physician or pharmacist should be consulted before using light therapy. In private use, care should be taken not to use devices for light therapy whose light spectrum also contains UV light. This is harmful to the eyes, so such lamps should not be used.In the case of light showers with UV-filtering lenses or caps, depending on the quality of the material, the UV light is not always completely absorbed. When using only blue light with a wavelength of 462 nm, which is generally considered the most effective form of light therapy, certain natural protective mechanisms in the eye cannot be activated. As a result, there is a higher risk of eye damage. This risk is eliminated by combining other colors with the blue light.