Light sensitivityorphotosensitivityrefers to a notable or increased reactivity to light. Apart fromvision,human beings have many physiological and psychological responses to light. In rare individuals an atypical response may result in serious discomfort, disease, or injury. Some drugs have a photosensitizing effect. Properties of natural or artificial light that may abnormally affect people include:
- Timing of light (upset of normalcircadian rhythms,seasonal affective disorder,sleep disorders)
- Intensity of light (photophobia,sunburn,skin cancer)[1][2][3]
- Wavelength of light (inlupus,urticaria)
- Rapid flickers in intensity of light may trigger or aggravatephotosensitive epilepsy,epileptic seizure,ormigraineheadaches.[4]
Conditions that may include sensitivity to light includevertigoandchronic fatigue syndrome.
Controlled application of artificial light can be used in a program oflight therapyto treat some disorders.
Sunlight
editSunlight, especially itsultraviolet radiationcomponent, can cause increased or additional types of damage in predisposed individuals, such as those taking certainphototoxicdrugs, or those with certain conditions associated with photosensitivity, including:
- Erythema multiforme[5]
- Seborrhoeic dermatitis[5]
- Autoimmunebullous diseases(immunobullous diseases)[5]
- Mycosis fungoides[5]
- Smith–Lemli–Opitz syndrome[5]
- Porphyria cutanea tarda
- Xeroderma pigmentosum
Also, many conditions are aggravated by strong light, including:
Fluorescent and LED lamps
editTheScientific Committee on Emerging and Newly Identified Health Risks(SCENIHR) in 2008 reviewed[6]the connections between light fromfluorescent lamps,especially fromcompact fluorescent lamp,and numerous human diseases, with results including:
- The inner-ear conditionMénière's diseasecan be aggravated by flicker. Sufferers ofvertigoare recommended to not use fluorescent lights.
- Polymorphous light eruptionis a condition affecting the skin thought to be caused by an adverse reaction to ultraviolet light. Its prevalence across Europe is 10-20% of the population. Artificial light sources may provoke the condition, and compact fluorescent light have been shown to produce an eruption.
- Chronic actinic dermatitisis a condition where a subject's skin becomes inflamed due to a reaction to sunlight or artificial light. Its prevalence inScotlandis 16.5 per 100,000 population. There is evidence that compact fluorescent light can worsen the condition.
- With the autoimmune diseaselupus,exposure to compact fluorescent lamps will induce disease activity in photosensitive SLE patients.
- There is evidence thatactinic prurigois worsened by compact fluorescent light. This disease affects 3.3% of the general population.
- 3.1% of the population[citation needed]suffer fromsolar urticaria,a skin disorder affected by ultraviolet light. Some patients are directly affected by compact fluorescent light.
- Phytophotodermatitismay be aggravated by the additional levels of ultraviolet light emitted by compact fluorescent light.
- Patients undergoingphotodynamic therapyare at additional risk of adverse photosensitive reactions caused by compact fluorescent light.
- One cause ofcataractsis exposure to ultraviolet light. Provided the level of UV emission from lamps is within safe limits, and the lamp a sufficient distance away from the individual, there should be no increased risk of developing cataracts.
- Photophobiais a symptom of excessive sensitivity to light which affects 5 to 20% of the population. Studies have shown that fluorescent lighting (which flickers 100 times a second) is twice as likely to cause headaches in office workers as non-flickering lights.[7]
- No similar studies have been conducted into the effect ofLED (light-emitting diode)lights on sufferers of photophobia but, because LED flickering is "even more pronounced", it is possible that LED lights are "even more likely to cause headaches".[7]
- There is evidence that flicker can causeseizuresin patients withphotosensitive epilepsy,but there has yet to be any evidence to date attributing seizures to compact fluorescent lamps.
- Self-reporting suggests fluorescent lamps aggravatedyslexia.
See also
editReferences
edit- ^Guide to Photophobia/Light Sensitivity,axonoptics. Retrieved 11 January 2019.
- ^Lightmare,lightmare.org. Retrieved 11 January 2019.
- ^"Blinded by Brighter Headlights? It’s Not Your Imagination.",The New York Times,5 June 2021. Retrieved 11 June 2021.
- ^Light and Sensitivity,headaches.org. Retrieved 11 January 2019.
- ^abcdefghijklmnEuropean Guidelines for Photodermatoses > 2 Photoaggravated Disorders[permanent dead link]at European Dermatology Forum
- ^"Light Sensitivity, Scientific Committee on Emerging and Newly Identified Health Risks"(PDF).Director-General for Health and Consumers, European Commission. 2008. pp.26–27.Retrieved2009-08-31.
- ^abArnold J. Wilkins,"The Scientific Reason You Don't Like LED Bulbs—and the Simple Way to Fix Them",Scientific American,1 August 2017. Retrieved 11 June 2019.