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The light therapy uses electromagnetic radiation with a certain wavelength and illuminance. It is mainly used for mental and dermatological diseases such as depression or psoriasis. Read everything about light therapy, how it works and the risks it carries.

What is light therapy?

In light therapy, the effect of various forms of light on the body is used. Classic light therapy uses radiation with bright fluorescent light, which, from a physical point of view, corresponds to sunlight. Mental illnesses are successfully treated with a strength of 2500 to 10000 lux, especially seasonal affective disorder (SAD).

Skin diseases can be effectively treated with the help of UV light (phototherapy). A special form of this is phototherapy. Infrared light relieves pain through its warming effect and promotes blood circulation. Newborn babies with jaundice are placed under a blue light therapy lamp for treatment.

When do you do light therapy?

Classic light therapy is used for the following diseases:

The use of a light therapy lamp - also known as a light shower - influences the internal clock, which is primarily controlled by solar radiation. If the days in autumn and winter get shorter or if this rhythm gets out of balance due to shift work, the body reacts with increased melatonin production. This so-called sleep hormone makes you tired - in too large quantities it can also lead to depression. At the same time, the serotonin level drops as the body converts serotonin into melatonin. Serotonin is considered a happiness hormone and, among other things, lifts the mood.

The bright light of the light shower brings the internal clock back into its rhythm and at the same time ensures that the serotonin level increases again.

UV-A and UV-B radiation (ultraviolet radiation) are mainly used for the therapy of dermatological diseases:

The so-called PUVA (psoralen and UV-A phototherapy) is one of the most effective forms of light therapy.

Further information: PUVA

If you want to know how to do a PUVA and what you have to pay attention to, read the article PUVA.

What do you do with light therapy?

Successful light therapy requires an illuminance of at least 2500 lux. A special light therapy device is required for this, as normal lightbulbs only emit around 300 to 800 lux.

The light shower emits a fluorescent, diffuse light with a broad spectrum, which corresponds most closely to natural sunlight. The light therapy unfolds its effect primarily through the absorption of light through the retina of the eye. In this way, it reaches the so-called nucleus suprachiasmaticus, a part of the brain that plays a decisive role as an impulse generator for the cicardial rhythm (daily rhythm) and thus also for the serotonin and melatonin level.

The light therapy device has a UV filter to protect the eyes from the harmful effects of UV light. The light shower is set up at a distance of half a meter to a full meter from the eyes. Depending on the level of illumination, you should be lit for between 30 minutes and two hours. An ideal time is the early morning hours between 5:30 a.m. and 8:00 a.m., as the light shower not only has an antidepressant but also a stimulating effect. You will achieve the best effect if you look directly into the light shower for a few seconds every minute.

The light therapy usually takes effect after three to four days. If the light therapy does not have any effect during this time, the illuminance can be increased or the duration of the illumination can be extended. An additional evening light shower is also helpful. The light therapy usually lasts a week, but can be repeated if the relapse occurs.

With UV-A or UV-B phototherapy, the skin is first irradiated two to three times a week with a low dose, which is then gradually increased. Various inflammatory cells in the skin are inhibited by the UV light. On average, phototherapy lasts five to eight weeks.

Newborn jaundice is a special case. A breakdown product of red blood cells, bilirubin, accumulates in the newborn's body and turns the skin and eyes yellow. If the bilirubin exceeds a certain value, brain damage can occur. This can be counteracted with color light therapy. Short-wave blue light helps the newborn to excrete bilirubin more quickly.

With this medically recognized exception, color light therapy is more likely to be classified in the wellness sector or among alternative healing methods. There are studies that indicate that the sight of certain colors could have an influence on the organism - an American study, for example, showed that people eat less from blue plates - but color light therapy is not medically recognized.

What are the risks of light therapy?

There are no known serious side effects with light therapy. Headache, eye irritation or a feeling of tension in the skin rarely occur. However, these complaints subside after a few hours. Blue light therapy can cause rashes, increased fluid loss and diarrhea in newborns. The UV radiation from phototherapy basically acts like natural sunlight and, in excess, is potentially carcinogenic and accelerates skin aging.

What do I have to consider during light therapy?

The success of the light shower therapy depends largely on the illuminance and the distance. Since every light therapy lamp can emit different lux values, you should ask your doctor about the exact application.

Regular treatment is also important, even on symptom-free days. Evening light therapy should only be carried out in consultation with your doctor, as a light shower can disrupt the circadian sleep-wake cycle. Certain drugs such as tricyclic antidepressants, neuroleptics or lithium increase light sensitivity. Therefore it should be taken before starting the light therapy an ophthalmological examination will be carried out. Prior consultation with an ophthalmologist is also recommended for all eye diseases.

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