Light therapy

Light therapy
Intervention

A light box in use for depression, seasonal affective disorder, or a circadian rhythm sleep disorder
ICD-10-PCS 6A6, GZJ
ICD-9: 99.83, 99.88
MeSH D010789

Light therapy or phototherapy (classically referred to as heliotherapy) consists of exposure to daylight or to specific wavelengths of light using polychromatic polarised light, lasers, light-emitting diodes, fluorescent lamps, dichroic lamps or very bright, full-spectrum light. The light is administered for a prescribed amount of time and, in some cases, at a specific time of day.

One common use of the term is associated with the treatment of skin disorders, chiefly psoriasis, acne vulgaris, eczema and neonatal jaundice.

Light therapy which strikes the retina of the eyes is used to treat circadian rhythm disorders such as delayed sleep phase disorder and can also be used to treat seasonal affective disorder, with some support for its use also with non-seasonal psychiatric disorders.

Medical uses

Skin conditions

Two forms of phototherapy exist: non-targeted phototherapy (from sunlight or a light box), and targeted phototherapy, in which light is administered to a specific, localized area of the skin. Current targeted phototherapy is administered via excimer laser, elemental gas lamp, or via LED light. Current FDA cleared devices on the market include XTRAC excimer laser,[1] BClear,[2] Theralight,[3] and Psoria-Light LED phototherapy.[4] Targeted phototherapy is administered in a doctor's office and is only administered to the affected skin, not the entire body, thus sparing healthy skin from UV rays which may lead to other health issues including skin cancer. While different wavelengths work for different conditions, treatment is most often done with narrow band UVB (NB-UVB) as this is the safest[5] wavelength. Non-targeted phototherapy can be delivered at doctor's office or at home via prescription (USA) using a booth, multidirectional unit, or wand.[6] The unaffected skin is simply covered. Several devices are FDA-approved for home including the Panosol 3D[7] and Richmond Light[8] and Solarc Handheld.[9]

Psoriasis

In psoriasis, UVB phototherapy has been shown to be effective.[10] A feature of psoriasis is localized inflammation mediated by the immune system.[11] Ultraviolet radiation is known to suppress the immune system and reduce inflammatory responses. Light therapy for skin conditions like psoriasis usually use NB-UVB (311 nm wavelength) though may use UV-A (315–400 nm wavelength) or UV-B (280–315 nm wavelength) light waves. UV-A, combined with psoralen, a drug taken orally, is known as PUVA treatment. In UVB phototherapy the exposure time is very short (seconds to minutes depending on intensity of lamps and the person's skin sensitivity). The time is controlled with a timer that turns off the lamps after the treatment time ends.

Vitiligo

One percent of the population suffer from vitiligo, and Narrowband UVB Phototherapy is an effective treatment. "NB-UVB phototherapy results in satisfactory repigmentation in our vitiligo patients and should be offered as a treatment option."[12]

Acne vulgaris

Evidence for light therapy and lasers in acne vulgaris as of 2012 is not sufficient to recommend them.[13] While light therapy appears to provide short term benefit, there is a lack of long term outcome data or data in those with severe acne.[14]

Cancer

According to the American Cancer Society, there is some evidence that ultraviolet light therapy may be effective in helping treat certain kinds of skin cancer, and ultraviolet blood irradiation treatment is established for this application. However, alternative uses of light for cancer treatment – light box therapy and colored light therapy – are not supported by evidence.[15]

Other skin conditions

Phototherapy can be effective in the treatment of eczema, atopic dermatitis, polymorphous light eruption,cutaneous T-cell lymphoma[16] and lichen planus. Narrowband UVB lamps, 311–313 nanometer is the most common treatment.

Wound healing

Some case studies[17] have found low-level laser light to be possibly helpful as an adjunctive treatment in wound healing, although a review of the overall scientific literature[18] does not support the use of low-level laser therapy for this purpose.

Mood and sleep related

Seasonal affective disorder

Full sunlight or exposure to bright light from a light box is used to treat seasonal affective disorder (SAD). Light boxes for SAD are designed to filter out most UV light, which can cause eye and skin damage.[19] Mayo Clinic states that light therapy has proven effectiveness for treating seasonal affective disorder and light therapy is seen as its main form of treatment.[20] Controlled-trial comparisons with antidepressants show equal effectiveness, with less expense and more rapid onset of therapeutic benefit, though a minority of patients may not respond to it.[21] Direct sunlight, reflected into the windows of a home or office by a computer-controlled mirror device called a heliostat, has also been used as a type of light therapy for the treatment of SAD.[22][23]

The effectiveness of light therapy for treating SAD may be linked to the fact that light therapy makes up for lost sunlight exposure and resets the body's internal clock.[24][25] Studies show that light therapy helps reduce the debilitating and depressive behaviors of SAD, such as excessive sleepiness and fatigue, which results lasting for at least 1 month. Light therapy is preferred over antidepressants in the treatment of SAD because it is a relatively safe and easy therapy.[26]

It is possible that response to light therapy for SAD could be season dependent.[27] Morning therapy has provided the best results because light in the early morning aids in regulating the circadian rhythm.[26]

Non-seasonal depression

Light therapy has also been suggested in the treatment of non-seasonal depression and other psychiatric disturbances, including major depressive disorder, bipolar disorder[28] and postpartum depression.[29][30] A meta-analysis by the Cochrane Collaboration concluded that "for patients suffering from non-seasonal depression, light therapy offers modest though promising antidepressive efficacy."[31] A more recent meta-analysis from Journal of Affective Disorders confirms this and is even more hopeful: "Overall, bright light therapy is an excellent candidate for inclusion into the therapeutic inventory available for the treatment of nonseasonal depression today, as adjuvant therapy to antidepressant medication, or eventually as stand-alone treatment for specific subgroups of depressed patients."[32]

Circadian rhythm sleep disorders

Chronic CRSD

In the management of circadian rhythm disorders such as delayed sleep phase disorder (DSPD), the timing of light exposure is critical. For DSPD, the light must be provided to the retina as soon after spontaneous awakening as possible to achieve the desired effect, as shown by the phase response curve for light in humans. Some users have reported success with lights that turn on shortly before awakening (dawn simulation). Morning use may also be effective for non-24-hour sleep–wake disorder, while evening use is recommended for advanced sleep phase disorder.

Situational CRSD

Light therapy has been tested for individuals on shift work,[33] and for jet lag.[34]

Sleep disorder in Parkinson's disease

Light therapy has been trialed in treating sleep disorders experienced by patients with Parkinson's disease.[35]

Neonatal jaundice

Further information: Neonatal jaundice
A newborn infant undergoing white-light phototherapy to treat neonatal jaundice.

Light therapy is used to treat cases of neonatal jaundice[36] through the isomerization of the bilirubin and consequently transformation into compounds that the newborn can excrete via urine and stools. A common treatment of neonatal jaundice is the bili light.

Techniques

Photodynamic therapy

Main article: Photodynamic therapy

Photodynamic therapy is a form of phototherapy using nontoxic light-sensitive compounds that are exposed selectively to light, whereupon they become toxic to targeted malignant and other diseased cells

One of the treatments is using blue light with aminolevulinic acid for the treatment of actinic keratosis. This is not a U.S. FDA-approved treatment for acne vulgaris.[37]

Light boxes

The brightness and color temperature of light from a light box are quite similar to daylight.

The production of the hormone melatonin, a sleep regulator, is inhibited by light and permitted by darkness as registered by photosensitive ganglion cells in the retina. To some degree, the reverse is true for serotonin, which has been linked to mood disorders. Hence, for the purpose of manipulating melatonin levels or timing, light boxes providing very specific types of artificial illumination to the retina of the eye are effective.

Light therapy uses either a light box which emits up to 10,000 lux of light at a specified distance, much brighter than a customary lamp, or a lower intensity of specific wavelengths of light from the blue (460 nm) to the green (525 nm) areas of the visible spectrum.[38] A 1995 study showed that green light therapy at doses of 350 lux produces melatonin suppression and phase shifts equivalent to 10,000 lux white light therapy,[39][40] but another study published in May 2010 suggests that the blue light often used for SAD treatment should perhaps be replaced by green or white illumination, because of a possible involvement of the cones in melatonin suppression.[41]

In treatment, the patient's eyes are to be at a prescribed distance from the light source with the light striking the (lower) retina. This does not require looking directly into the light.

Considering three major factors – clinical efficacy, ocular and dermatologic safety, and visual comfort, the Center for Environmental Therapeutics (CET) recommends the following criteria for light box selection:[42]

Risks and complications

Ultraviolet light causes progressive damage to human skin.[44] This 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 to be a factor in formation of cataracts.

Researchers have questioned whether limiting blue light exposure could reduce the risk of age-related macular degeneration.[45]

Modern phototherapy lamps used in the treatment of seasonal affective disorder and sleep disorders either filter out or do not emit ultraviolet light and are considered safe and effective for the intended purpose, as long as photosensitizing drugs are not being taken at the same time and in the absence of any existing eye conditions. Light therapy is a mood altering treatment, and just as with drug treatments, there is a possibility of triggering a manic state from a depressive state, causing anxiety and other side effects. While these side effects are usually controllable, it is recommended that patients undertake light therapy under the supervision of an experienced clinician, rather than attempting to self-medicate.[46]

It is reported that bright light therapy may activate the production of reproductive hormones, such as testosterone, luteinizing hormone, follicle-stimulating hormone, and estradiol.[47][48]

There are few absolute contraindications to light therapy, although there are some circumstances in which caution is required. These include when a patient has a condition that might render his or her eyes more vulnerable to phototoxicity, has a tendency toward mania, has a photosensitive skin condition, or is taking a photosensitizing herb (such as St. John's wort) or medication.[49] Patients with porphyria should avoid most forms of light therapy. Patients on certain drugs such as methotrexate or chloroquine should use caution with light therapy as there is a chance that these drugs could cause porphyria.

Side effects

Side effects of light therapy for sleep phase disorders include jumpiness or jitteriness, headache, eye irritation and nausea.[50] Some nondepressive physical complaints (such as poor vision and skin rash or irritation) may improve with light therapy.[51]

History

Many ancient cultures practiced various forms of heliotherapy, including people of Ancient Greece, Ancient Egypt, and Ancient Rome.[52] The Inca, Assyrian and early German settlers also worshipped the sun as a health bringing deity. Indian medical literature dating to 1500 BC describes a treatment combining herbs with natural sunlight to treat non-pigmented skin areas. Buddhist literature from about 200 AD and 10th-century Chinese documents make similar references.

The Faroese physician Niels Finsen is believed to be the father of modern phototherapy. He developed the first artificial light source for this purpose. Finsen used short wavelength light to treat lupus vulgaris, a skin infection caused by Mycobacterium tuberculosis. He thought that the beneficial effect was due to ultraviolet light killing the bacteria, but recent studies showed that his lens and filter system did not allow such short wavelengths to pass through, leading instead to the conclusion that light of approximately 400 nanometers generated reactive oxygen that would kill the bacteria.[53] Finsen also used red light 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 later eradication of smallpox and development of antibiotics for tuberculosis rendered light therapy obsolete for these diseases.[54]

Since then a large array of treatments using controlled light have been developed. Though the popular consumer understanding of "light therapy" is associated with treating seasonal affective disorder, circadian rhythm disorders and skin conditions like psoriasis, other applications include the use of low level laser, red light, near-infrared and ultraviolet lights for pain management, hair growth, skin treatments, and accelerated wound healing.

See also

References

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  11. ↑ "What is Psoriasis: What Causes Psoriasis?". 29 January 2012. Retrieved 11 July 2012.
  12. ↑ Adauwiyah J, Suraiya HH (December 2010). "A retrospective study of narrowband-UVB phototherapy for treatment of vitiligo in Malaysian patients". Med. J. Malaysia 65 (4): 297–9. PMID 21901949.
  13. ↑ Titus S, Hodge J (October 2012). "Diagnosis and treatment of acne". Am Fam Physician 86 (8): 734–40. PMID 23062156.
  14. ↑ Hamilton FL, Car J, Lyons C, Car M, Layton A, Majeed A (June 2009). "Laser and other light therapies for the treatment of acne vulgaris: systematic review". Br. J. Dermatol. 160 (6): 1273–85. doi:10.1111/j.1365-2133.2009.09047.x. PMID 19239470.
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  16. ↑ http://www.ncbi.nlm.nih.gov/pubmed/14686973. Missing or empty |title= (help)
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  25. ↑ "Researchers suggest SAD Syndrome is caused by a mis-timed sleep-wake rhythm". Re-Timer Blog. Flinders University. Retrieved 15 October 2014.
  26. ↑ 26.0 26.1 Sanassi, Lorraine A. "Seasonal affective disorder: Is there light at the end of the tunnel?." Journal of the American Academy of Physician Assistants 27.2 (2014): 18-22.
  27. ↑ Thompson C, Stinson D, Smith A (September 1990). "Seasonal affective disorder and season-dependent abnormalities of melatonin suppression by light". Lancet 336 (8717): 703–6. doi:10.1016/0140-6736(90)92202-S. PMID 1975891.
  28. ↑ Benedetti F, Colombo C, Pontiggia A, Bernasconi A, Florita M, Smeraldi E, (2003) Morning light treatment hastens the antidepressant effect of citalopram: a placebo-controlled trial, J Clin Psychiatry. Jun; 64(6) 648-53.
  29. ↑ Prasko J (November 2008). "Bright light therapy". Neuro Endocrinol. Lett. 29 Suppl 1: 33–64. PMID 19029878.
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  31. ↑ Tuunainen, A; Kripke, DF; Endo, T (2004). Tuunainen, Arja, ed. "Light therapy for non-seasonal depression". Cochrane Database of Systematic Reviews (2): CD004050. doi:10.1002/14651858.CD004050.pub2. PMID 15106233.
  32. ↑ Even, C; Schröder, CM; Friedman, S; Rouillon, F (2008). "Efficacy of light therapy in nonseasonal depression: A systematic review". Journal of Affective Disorders 108 (1–2): 11–23. doi:10.1016/j.jad.2007.09.008. PMID 17950467.
  33. ↑ Smith MR, Eastman CI (December 2008). "Night shift performance is improved by a compromise circadian phase position: study 3. Circadian phase after 7 night shifts with an intervening weekend off". Sleep 31 (12): 1639–45. PMC 2603486. PMID 19090319.
  34. ↑ Brown GM, Pandi-Perumal SR, Trakht I, Cardinali DP (March 2009). "Melatonin and its relevance to jet lag". Travel Med Infect Dis 7 (2): 69–81. doi:10.1016/j.tmaid.2008.09.004. PMID 19237140.
  35. ↑ Willis, G. L., Moore, C. & Armstrong, S. M. (2012). “A historical justification for and retrospective analysis of the systematic application of light therapy in Parkinson’s disease”. Reviews in the Neurosciences, 23 (2): 199-226., Doi:PMID: 22499678.
  36. ↑ Newman TB, Kuzniewicz MW, Liljestrand P, Wi S, McCulloch C, Escobar GJ (May 2009). "Numbers needed to treat with phototherapy according to American Academy of Pediatrics guidelines". Pediatrics 123 (5): 1352–9. doi:10.1542/peds.2008-1635. PMC 2843697. PMID 19403502.
  37. ↑ "Phototherapy for Acne". Aetna.com. Retrieved 2015-02-25.
  38. ↑ Wright HR, Lack LC, Kennaway DJ. (March 2004). "Differential effects of light wavelength in phase advancing the melatonin rhythm". J. Pineal Res. 36 (2): 140–4. doi:10.1046/j.1600-079X.2003.00108.x. PMID 14962066.
  39. ↑ Saeeduddin Ahmed, Neil L Cutter, Alfred J. Lewy, Vance K. Bauer, Robert L Sack and Mary S. Cardoza (1995). "Phase Response Curve of Low-Intensity Green Light in Winter Depressives". Sleep Research 24: 508. doi:10.1186/1471-244X-5-42. The magnitude of the phase shifts [using low-level green light therapy] are comparable to those obtained using high-intensity white light in winter-depressives.
  40. ↑ Michel A. Paul, James C. Miller, Gary Gray, Fred Buick, Sofi Blazeski and Josephine Arendt (July 2007). "Circadian Phase Delay Induced by Phototherapeutic Devices". Sleep Research 78 (7): 645–652.
  41. ↑ J.J. Gooley, S.M.W. Rajaratnam, G.C. Brainard, R.E. Kronauer, C.A. Czeisler, S.W. Lockley (May 2010). "Spectral Responses of the Human Circadian System Depend on the Irradiance and Duration of Exposure to Light". Science Translational Medicine 2 (31): 31–33. doi:10.1126/scitranslmed.3000741. PMID 20463367.
  42. ↑ "Light Box Selection". Center for Environmental Therapeutics. CET. Retrieved 25 May 2011.
  43. ↑ Glickman, G; Byrne, B; Pineda, C; Hauck, WW; Brainard, GC (Mar 15, 2006). "Light therapy for seasonal affective disorder with blue narrow-band light-emitting diodes (LEDs).". Biological Psychiatry 59 (6): 502–7. doi:10.1016/j.biopsych.2005.07.006. PMID 16165105.
  44. ↑ Barkham. "One face, but two sides of a story". Theguardian.com. Retrieved 7 October 2014.
  45. ↑ Glazer-Hockstein C, Dunaief JL (January 2006). "Could blue light-blocking lenses decrease the risk of age-related macular degeneration?". Retina (Philadelphia, Pa.) 26 (1): 1–4. doi:10.1097/00006982-200601000-00001. PMID 16395131.
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  47. ↑ "Bright Light May Boost Testosterone". WebMD. Retrieved 2008-12-15.
  48. ↑ Danilenko KV, Samoilova EA (2007). "Stimulatory effect of morning bright light on reproductive hormones and ovulation: results of a controlled crossover trial". PLoS Clin Trials 2 (2): e7. doi:10.1371/journal.pctr.0020007. PMC 1851732. PMID 17290302.
  49. ↑ Gagarina, AK (2007-12-08). "Light Therapy Diagnostic Indications and Contraindications". American Medical Network. Retrieved 2009-06-09.
  50. ↑ Mayo Clinic Staff (20 March 2013). "Light Therapy. Tests and Procedures. Risks.". Mayo Clinic. Retrieved 7 February 2014.
  51. ↑ Roger DR (2007-12-04). "Practical aspects of light therapy". American Medical Network. Retrieved 2009-06-09.
  52. ↑ F. Ellinger Medical Radiation Biology Springfield 1957
  53. ↑ "How Finsen's light cured lupus vulgaris. - PubMed - NCBI". Ncbi.nlm.nih.gov. 2014-11-12. Retrieved 2015-02-25.
  54. ↑ "Engines of our Ingenuity No. 1769: NIELS FINSEN". Retrieved 2014-04-05.

External links

Media related to Phototherapy at Wikimedia Commons