Light therapy - or phototherapy , classically referred to as heliotherapy - consists of exposure to sunlight or specific wavelengths of light using polychromatically polarized light, lasers, light-emitting diodes, fluorescent lamps, dichroic lights or very bright full-spectrum light. Light is given for the amount of time specified and, in some cases, at certain times of the day.
One common use of this term is associated with the treatment of skin disorders, especially psoriasis, acne vulgaris, eczema and neonatal jaundice.
Light therapy that attacks the retina of the eye is used to treat diabetic retinopathy as well as circadian rhythm disturbances such as delayed sleep phase disorder and can also be used to treat seasonal affective disorder, with some support for its use as well as with non-seasonal psychiatric disorders..
Video Light therapy
Medical use
Skin condition
Treatment involves exposing skin to ultraviolet light. Exposure can be to a small area of ​​skin or above the entire body surface, such as in a tanning bed. The most common treatment is narrowband UVB (NB-UVB) with a wavelength of 311-313 nanometers. It was found that this was the safest treatment. Whole body phototherapy can be given at the doctor's office or at home using a large-capacity UVB booth.
Atopic dermatitis
Light therapy is considered one of the best monotherapy treatments for atopic dermatitis (AD), when applied to patients who have not responded to traditional topical treatments. This therapy offers various options: UVA1 for acute AD, NB-UVB for chronic AD, and balneophototherapy have proven their efficacy in the past. Patients tolerate therapy safely but, as in any therapy, side effects and treatments should be taken in the application, especially for children.
Psoriasis
For psoriasis, UVB phototherapy has proven to be effective. A feature of psoriasis is local inflammation that is mediated by the immune system. Ultraviolet radiation is known to suppress the immune system and reduce the inflammatory response. Light therapy for skin conditions such as psoriasis usually uses NB-UVB (wavelength 311 n) although it may use UV-A wavelength wavelength (wavelength 315-400 Âμm) or UV-B light waves (wavelength 280-315 nm). UV-A, combined with psoralen, an orally taken drug, is known as PUVA treatment. In UVB phototherapy, the exposure time is very short, seconds to minutes depending on the intensity of the lamp and the pigment and the sensitivity of the person's skin. The time is controlled by a timer that turns off the light after the end of maintenance.
Vitiligo
One percent of the population suffers from vitiligo, and UVB narrowband phototherapy is an effective treatment. "NB-UVB phototherapy produces satisfactory repigmentation in our vitiligo patients and should be offered as a treatment option."
Acne vulgaris
Evidence for light and laser therapy in acne vulgaris in 2012 is not enough to recommend them. There is moderate evidence for the efficacy of blue and blue-red light therapy in treating mild acne, but most studies have low quality. While light therapy seems to provide short-term benefits, there is a lack of data or long-term outcome data in those with severe acne.
Cancer
According to the American Cancer Society, there is some evidence that ultraviolet light therapy may be effective in helping treat some types of skin cancer, and ultraviolet blood irradiation therapy is established for this application. However, alternative use of light for cancer treatment - light box therapy and colored light therapy - is not supported by evidence. Photodynamic therapy (often with red light) is used to treat certain superficial non-melanoma skin cancers.
Other skin conditions
Phototherapy can be effective in the treatment of eczema, atopic dermatitis, polymorph glow eruption, cutaneous T cell lymphoma and lichen planus. Narrowband UVB Lamp, 311-313 nanometers is the most common treatment.
Wound healing
Low-level laser therapy has been studied as a potential treatment for chronic wounds. A review of the scientific literature does not support the widespread use of this technique because of inconsistent results and low quality of research. Higher power lasers have also been used to seal acute wounds as an alternative to stitches.
Retinal conditions
There is early evidence that light therapy is an effective treatment for diabetic retinopathy and diabetic macular edema.
Seasonal affective disorder
The effectiveness of light therapy to treat SAD may be related to the fact that light therapy covers the exposure to sunlight lost and resets the body's internal clock. Studies show that light therapy helps reduce debilitating behavior and SAD depression, such as excessive sleepiness and fatigue, with results lasting at least 1 month. Light therapy is preferred over antidepressants in the treatment of SAD because it is a relatively safe and easy therapy.
It is possible that the response to light therapy for SAD may depend on the season. Morning therapy has given the best results because the light in the morning helps regulate the circadian rhythm.
A systematic review of 2007 by the Swedish agency SBU found insufficient evidence that light therapy was able to relieve symptoms of depression or seasonal affective disorder. The report recommends that: "Around 100 participants were asked to determine whether the therapy was effective compared with placebo". Although treatment in the light therapy room is well established in Sweden, no satisfactory and controlled studies have been published on the subject. This led to the closure of a number of clinics offering light therapy in Sweden.
Non-seasonal depression
Light therapy has also been suggested in the treatment of non-seasonal depression and other psychiatric mood disorders, including major depressive disorder, bipolar disorder and postpartum depression. A meta-analysis by Cochrane Collaboration concluded that "for patients suffering from non-seasonal depression, light therapy offers a promising but simple antidepressive efficacy." A systematic review of 2008 concluded that "overall bright light therapy is an excellent candidate for inclusion in therapeutic supplies available for the treatment of non-depressive depression today, as an adjuvant therapy for antidepressant drugs, or ultimately as stand-alone treatment for certain subgroups are depressed patients. "A review of 2015 found that supporting evidence for light therapy is limited due to a serious methodological defect.
Sleep disorders circadian rhythms and jet lag
Sleep disorder chronic circadian rhythm (CRSD)
In the management of circadian rhythm disorders such as delayed sleep phase disorder (DSPD), light exposure time is very important. Exposure to light given to the eye before or after the nadir rhythm of the core body temperature may affect the phase response curve. Wake-up use is also effective for 24-hour sleep-wake disorders. Some users have reported success with lights that light up shortly before wake up (dawn simulation). Night usage is recommended for people with advanced sleep phase disorders. Some, but not all, people whose total blindness is retinaanya still intact, may benefit from light therapy.
Situational CRSD
Light therapy has been tested for individuals with sleep shift work disorder, and for jet lag.
Sleep disorders in Parkinson's disease
Light therapy has been tested in treating sleep disorders experienced by patients with Parkinson's disease.
Neonatal jaundice (Postnatal General)
Light therapy is used to treat cases of neonatal jaundice through bilirubin isomerization and consequently transformation into compounds that infants can excrete through urine and feces. The general treatment of neonatal jaundice is biliary or billiblanket light.
Maps Light therapy
Technique
Photodynamic therapy
Photodynamic therapy is a form of phototherapy using light-sensitive toxic compounds exposed selectively to light, so they become toxic to targeted malignant cells and other diseased cells.
One treatment uses blue light with aminolevulinic acid for the treatment of actinic keratoses. This is not a US FDA-approved treatment for acne vulgaris.
Lightbox
The production of the hormone melatonin, the sleep regulator, is inhibited by light and permitted by darkness as listed by the photosensitive ganglion cell in the retina. To some degree, the opposite is true for serotonin, which has been linked to mood disorders. Therefore, for the purpose of manipulating the level or timing of melatonin, the light boxes that provide a very specific kind of artificial illumination in the effective retina of the eye.
Light therapy uses light boxes that emit up to 10,000 lux light at a certain distance, much brighter than ordinary lights, or lower intensity of certain light wavelengths from blue (460 nm) to green (525 n nm) visible spectral regions. A 1995 study showed that green light therapy at a dose of 350 lux resulted in melatonin suppression and a phase shift equivalent to 10,000 white light therapy, but another study published in May 2010 showed that blue light often used for SAD treatment may have to be replaced by green. or white illumination, because of the possibility of cone involvement in melatonin suppression.
In care, the patient's eye should be at a specified distance from the light source with a striking light on the retina (below). It does not need to look directly into the light.
Considering three main factors - clinical efficacy, ocular safety and dermatology, and visual comfort, the Center for Environmental Therapy (CET) recommends the following criteria for light box selection:
- Light boxes should have been successfully tested in peer-reviewed clinical trials.
- The box should provide 10,000 lux lighting at comfortable sitting distances. Product specifications are often missing or unverified; lighting can be controlled using a light meter.
- The fluorescent lamp should have a fine diffuse screen that filters out ultraviolet (UV) rays. UV rays are harmful to the eyes and skin.
- Blue light is known to be superior to red light in managing symptoms of depression that have seasonal patterns.
- Light should be projected downward toward the eye at an angle to minimize the distracting visual glare.
- Smaller is no better; when using a compact light box, even a small head movement will take the eyes out of the therapeutic range of light.
Light induced thermogenesis
A recent study proposes a theoretical model that can be used to treat obesity and diabetes, using light induced thermogenesis.
Risks and complications
Ultraviolet
Ultraviolet light causes progressive damage to human skin and erythema even from small doses. It is mediated by genetic damage, collagen damage, as well as destruction of vitamin A and vitamin C in the skin and free radical generation. Ultraviolet light is also known as a factor in cataract formation. Exposure to ultraviolet radiation is strongly associated with the incidence of skin cancer.
Visible light
Any optical radiation of any kind with sufficient intensity can cause damage to the eyes and skin including photoconjunctivitis and fotokeratitis. The researchers questioned whether limiting blue light exposure could reduce the risk of age-related macular degeneration. It was reported that bright light therapy may activate the production of reproductive hormones, such as testosterone, luteinizing hormone, follicle stimulating hormone, and estradiol.
Modern phototherapy lamps used in the treatment of seasonal affective disorder and sleep disturbance either filter or do not emit ultraviolet light and are considered safe and effective for intended purpose, as long as photosensitizing drugs are not taken at the same time and in the absence of existing eye conditions. Light therapy is a mood-altering treatment, and as with drug treatment, it is possible to trigger a mania state from a state of depression, causing anxiety and other side effects. Although these side effects can usually be controlled, it is recommended that the patient perform light therapy under the supervision of an experienced doctor, rather than trying to self-medicate.
Contraindications to light therapy for seasonal affective disorders include conditions that can make the eyes more susceptible to phototoxicity, mania tendencies, sensitive skin conditions, or the use of photosensitizing herbs (such as St. John's wort) or drugs. Patients with porphyria should avoid most forms of light therapy. Patients with certain medications such as methotrexate or chloroquine should be careful with light therapy because it is possible that this drug may cause porphyria.
Side effects of light therapy for sleep phase disorders include anxiety or restlessness, headache, eye irritation and nausea. Some non-depressive physical complaints, such as poor vision and rash or skin irritation, may improve with light therapy.
History
Many ancient cultures practice various forms of heliotherapy, including Ancient Greeks, Ancient Egyptians, and Ancient Romans. The Inca, Assyrian and early German settlers also worshiped the sun as a god who brought health. The Indian medical literature dating from 1500 BC describes a treatment that combines herbs with natural sunlight to treat non-pigmented skin areas. The Buddhist literature of about 200 AD and the 10th century Chinese documents make similar references.
Doctor Faroese Niels Finsen is believed to be the father of modern phototherapy. He developed the first artificial light source for this purpose. Finsen uses short-wavelength light to treat lupus vulgaris, a skin infection caused by Mycobacterium tuberculosis . He thinks that the beneficial effect is due to the ultraviolet light that kills bacteria, but recent research shows that the lens and filter system do not allow such short wavelengths to pass through, leading to the conclusion that a light of around 400 nanometers produces reactive oxygen that will kill bacteria. Finsen also uses red lights to treat smallpox lesions. He received the Nobel Prize in Physiology or Medicine in 1903. Scientific evidence for some of his treatments is lacking, and then the eradication of smallpox and the development of antibiotics for tuberculosis makes light therapy obsolete for this disease.
From the late nineteenth to early 1930s, light therapy was considered an effective and mainstream medical therapy in the UK for conditions such as varicose ulcers, 'sick children' and other conditions. Controlled trials by medical scientist Dora Colebrook, backed by the Medical Research Council, show that light therapy is ineffective for a variety of conditions.
Since then a large number of treatments using controlled light have been developed. Although popular consumer understanding of "light therapy" is associated with treating seasonal affective disorders, impaired circadian rhythm and skin conditions such as psoriasis, other applications include low-level laser use, red light, near infrared and ultraviolet light for pain management, hair growth, skin care , and accelerated wound healing.
See also
- Blood irradiation therapy
- Deep sleep
- Low-level laser therapy
- Sun tanning
- UV-B lights
References
External links
Media related to Phototherapy on Wikimedia Commons
- Our Friends, Sun: Light Therapy Image from Osler Library Collection, c. 1901-1944. Digital exhibition by Osler Library of Medicine History, McGill University
Source of the article : Wikipedia
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