Abnormal intolerance to visual perception of light
This article is about the human medical symptom. For the biological or botanical behavioral property, seePhotophobia (biology). For the morbid fear of light, seeHeliophobia. For the 2023 film, seePhotophobia (film).
Photophobia is a medicalsymptom of abnormal intolerance to visual perception oflight.[1] As a medical symptom, photophobia is not a morbid fear orphobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical sensitivity of the eyes,[2] though the term is sometimes additionally applied to abnormal or irrationalfear of light, such asheliophobia.[3] The termphotophobia comes from Greek φῶς (phōs)'light' and φόβος (phóbos)'fear'.[4][5]
Patients may develop photophobia as a result of several different medical conditions, related to theeye, thenervous system, genetic, or other causes.[citation needed]
Photophobia may manifest itself in an increased response to light starting at any step in thevisual system, such as:[citation needed]
Too much light entering the eye. Too much light can enter the eye if it is damaged, such as withcorneal abrasion and retinal damage, or if its pupil is unable to normally constrict (seen with damage to theoculomotor nerve).
Due toalbinism, the lack of pigment in the colored part of the eyes (irises) makes them somewhat translucent. This means that the irises cannot completely block light from entering the eye.
Trigeminal disturbance causescentral sensitization (hence, multiple other associated hypersensitivities). Causes can be bad bite, infected tooth, etc.[17]
Treatment for light sensitivity addresses the underlying cause, whether it be an eye, nervous system or other cause. If the triggering factor or underlying cause can be identified and treated, photophobia may disappear. Tinted glasses are sometimes used.[33]
People with photophobia may feel eye pain from even moderate levels of artificial light and avert their eyes from artificial light sources. Ambient levels of artificial light may also be intolerable to people afflicted with photophobia such that they dim or remove the light source, or go into a dimmer lit room, such a one lit by refraction of light from outside the room. Alternatively, they may wear darksunglasses, sunglasses designed to filterperipheral light, precision tinted glasses, and/or wide-brimmedsun hats orbaseball caps. Some types of photophobia may be helped with the use of precision tinted lenses which block the green-to-blue end of the light spectrum without blurring or impeding vision.[34][35]
Other strategies for relieving photophobia include the use of tinted contact lenses and/or the use of prescription eye drops that constrict the pupil, thus reducing the amount of light entering the eye. Such strategies may be limited by the amount of light needed for proper vision under given conditions, however. Dilating drops may also help relieve eye pain from muscle spasms or seizures triggered by lighting/migraine, allowing a person to "ride out the migraine" in a dark or dim room. A paper by Stringham and Hammond, published in theJournal of Food Science, reviews studies of effects of consuminglutein andzeaxanthin on visual performance, and notes a decrease in sensitivity to glare.[36]
Photophobia may preclude or limit a person from working in places where lighting is used, unless the person is able to obtain a reasonable accommodation like being allowed to wear tinted glasses. Some people with photophobia may thereby be better able to work at night or be more easily accommodated in the workplace at night.[citation needed]
Outdoor night lighting may be equally offensive for persons with photophobia, however, given the wide variety of bright lighting used for illuminating residential, commercial and industrial areas, such asLED (light-emitting diode) lamps.[37][38]
The increasing popularity of "overpoweringly intense" LED headlights being used on "pickups andS.U.V.s" has prompted more frequent reports of photophobia among motorists, cyclists, and pedestrians.[39]
The American Heritage Medical Dictionary Copyright 2007
Millodot: Dictionary of Optometry and Visual Science, 7th edition. 2009
^φῶς, Henry George Liddell, Robert Scott,A Greek-English Lexicon, on Perseus
^φόβος, Henry George Liddell, Robert Scott,A Greek-English Lexicon, on Perseus
^Hazin R, Abuzetun JY, Daoud YJ, Abu-Khalaf MM (July 2009). "Ocular complications of cancer therapy: a primer for the ophthalmologist treating cancer patients".Current Opinion in Ophthalmology.20 (4):308–317.doi:10.1097/ICU.0b013e32832c9007.PMID19491683.S2CID205670593.
^"Achromotopsoa". Scottish Sensory Centre. RetrievedDecember 11, 2009.
^Fan X, Miles JH, Takahashi N, Yao G (November 2009). "Abnormal transient pupillary light reflex in individuals with autism spectrum disorders".Journal of Autism and Developmental Disorders.39 (11):1499–1508.doi:10.1007/s10803-009-0767-7.PMID19499319.S2CID32110116.
^Cooper AD, Josephs, KA (2009). "Photophobia, visual hallucinations, and REM sleep behavior disorder in progressive supranuclear palsy and corticobasal degeneration: a prospective study".Parkinsonism & Related Disorders.15 (1):59–61.doi:10.1016/j.parkreldis.2008.01.011.PMID18328771.
^Pelissolo A, Bisserbe JC (March–April 1994). "Dépendance aux benzodiazépines. Aspects cliniques et biologiques" [Dependence on benzodiazepines. Clinical and biological aspects].Encephale (in French).20 (2):147–157.PMID7914165.
