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Photophobia
 
 
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Photophobia is a symptom
Symptom

A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality. A symptom is subjective, observed by the patient, and not measured....
 of excessive sensitivity
Sensitivity (human)

The sensitivity or insensitivity of a human, often considered with regard to a particular kind of stimulation, is the strength of the feeling it results in, in comparison with the strength of the stimulus....
 to light
Light

Light, or visible light, is electromagnetic radiation of a wavelength that is Visible spectrum to the human eye , or up to 380?750 nm. In the broader field of physics, light is sometimes used to refer to electromagnetic radiation of all wavelengths, whether visible or not....
 and the aversion to sunlight
Sunlight

Sunlight, in the broad sense, is the total spectroscopy of the electromagnetic radiation given off by the Sun. On Earth, sunlight is Filter ed through the Earth's atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon....
 or well-lit places. In medical terms it is not fear, but an experience of discomfort or pain to the eyes due to light exposure.

Light sensitivity is usually due to too much light entering the eye, which causes over stimulation of the photoreceptor
Photoreceptor

A photoreceptor, or photoreceptor cell, is a specialized type of neuron found in the eye's retina that is capable of phototransduction....
s in the retina
Retina

The vertebrate retina is a light sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera....
 and subsequent excessive electric impulses to the optic nerve
Optic nerve

The optic nerve, also called cranial nerve II, transmits visual information from the retina to the brain....
. This leads to a reflex aversion to light, and discomfort or pain.






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Encyclopedia


Photophobia is a symptom
Symptom

A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality. A symptom is subjective, observed by the patient, and not measured....
 of excessive sensitivity
Sensitivity (human)

The sensitivity or insensitivity of a human, often considered with regard to a particular kind of stimulation, is the strength of the feeling it results in, in comparison with the strength of the stimulus....
 to light
Light

Light, or visible light, is electromagnetic radiation of a wavelength that is Visible spectrum to the human eye , or up to 380?750 nm. In the broader field of physics, light is sometimes used to refer to electromagnetic radiation of all wavelengths, whether visible or not....
 and the aversion to sunlight
Sunlight

Sunlight, in the broad sense, is the total spectroscopy of the electromagnetic radiation given off by the Sun. On Earth, sunlight is Filter ed through the Earth's atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon....
 or well-lit places. In medical terms it is not fear, but an experience of discomfort or pain to the eyes due to light exposure.

Light sensitivity is usually due to too much light entering the eye, which causes over stimulation of the photoreceptor
Photoreceptor

A photoreceptor, or photoreceptor cell, is a specialized type of neuron found in the eye's retina that is capable of phototransduction....
s in the retina
Retina

The vertebrate retina is a light sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera....
 and subsequent excessive electric impulses to the optic nerve
Optic nerve

The optic nerve, also called cranial nerve II, transmits visual information from the retina to the brain....
. This leads to a reflex aversion to light, and discomfort or pain. Too much light can enter the eye if it is damaged, such as with corneal abrasion and retinal damage, or if a pupil(s) is unable to normally constrict (seen with damage to the oculomotor nerve
Oculomotor nerve

The oculomotor nerve is the third of twelve paired cranial nerves. It controls most of the eye's movements, constriction of the pupil, and maintains an open eyelid....
).

Patients with photophobia will avert their eyes from direct light (sunlight and room lights), or may seek the shelter of a dark room or wear sunglasses.

Photophobia is also a behavior demonstrated by insects or other animals which seek to stay out of the light.

Causes

Patients may develop photophobia as a result of several different medical conditions, related to the eye
Eye

Eyes are Organ that detect light, and send signals along the optic nerve to the visual system and other areas of the brain. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system....
 or the nervous system
Nervous system

The nervous system is a Neural network of specialized cells that communicate information about an animal's surroundings and itself. It processes this information and causes reactions in other parts of the body....
.

  • Meningitis
    Meningitis

    Meningitis is a medical condition caused by inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges....
  • Magnesium Deficiency
    Magnesium deficiency

    Magnesium deficiency is a plant disorder with two main causes. Magnesium can be easily washed out of light soils in wet seasons or excessive potassium fertilizer usage can cause also Mg to become unavailable to the growing plant....
  • Benzodiazepines (long term use of or withdrawal from benzodiazepines)
  • Eye
    Eye

    Eyes are Organ that detect light, and send signals along the optic nerve to the visual system and other areas of the brain. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system....
     disease, injury, or infection such as chalazion
    Chalazion

    A chalazion , also known as a meibomian gland lipogranuloma, is a cyst in the eyelid that is caused by inflammation of a blocked meibomian gland, usually on the upper eyelid....
    , episcleritis, glaucoma
    Glaucoma

    Glaucoma is a group of diseases of the optic nerve involving loss of ganglion cell in a characteristic pattern of optic atrophy. Raised intraocular pressure is a significant risk factor for developing glaucoma ....
    , keratoconus
    Keratoconus

    Keratoconus , is a degenerative disorder of the eye in which structural changes within the cornea cause it to thin and change to a more Cone shape than its normal gradual curve....
  • Subarachnoid haemorrhage
  • Albinism
    Albinism

    Albinism is a form of hypopigmentation congenital disorder, characterized by a partial or total lack of melanin Biological pigment in the eyes, skin and hair ....
  • Burns to the eye
    Eye

    Eyes are Organ that detect light, and send signals along the optic nerve to the visual system and other areas of the brain. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system....
  • Migraine
    Migraine

    Migraine is a neurology syndrome characterized by altered bodily perceptions, headaches, and nausea. Physiologically, the migraine headache is a neurological condition more common to women than to men....
    s
  • Encephalitis
    Encephalitis

    Not to be confused with syphilis, although that can cause encephalitis as well.Encephalitis is an Acute inflammation of the brain.Encephalitis with meningitis is known as meningoencephalitis....
  • Conjunctivitis
    Conjunctivitis

    Conjunctivitis is an inflammation of the conjunctiva , most commonly due to an allergic reaction or an infection ....
  • Aphakia
    Aphakia

    Aphakia is the absence of the Lens of the eye, due to surgical removal, a perforation wound or Corneal ulcer, or congenital anomaly. It causes a loss of accommodation , hyperopia, and a deep anterior chamber....
  • Iritis
    Iritis

    Iritis is a form of anterior uveitis and refers to the inflammation of the iris of the eye....
  • Aniridia
    Aniridia

    Aniridia is a rare congenital condition characterized by the underdevelopment of the eye's iris . This usually occurs in both eyes. It is associated with poor development of the retina at the back of the eye preventing normal vision development....
  • Corneal abrasion
    Corneal abrasion

    Corneal abrasion is a medical condition involving the loss of the surface epithelial layer of the eye's cornea....
  • Corneal ulcer
    Corneal ulcer

    A corneal ulcer, or ulcerative keratitis, is an inflammatory condition of the cornea involving loss of its outer layer. It is very common in dogs and is sometimes seen in cats....
  • Cataracts
  • Retinal detachment
    Retinal detachment

    Retinal detachment is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized, but without rapid treatment the entire retina may detach, leading to vision loss and blindness....
  • Dilation
    Dilation

    Dilation or dilatation may refer to:In physiology:* Pupillary response, dilation of the pupil of the eye* Cervical dilation, the widening of the cervix in childbirth, miscarriage etc....
     (naturally or chemically induced)
  • Chiari malformation
  • Cystinosis
    Cystinosis

    Cystinosis is a lysosomal storage disease characterized by the abnormal accumulation of the amino acid cystine. It is a genetic disorder that typically follows an dominance relationship inheritance pattern....
  • Anticholinergic
    Anticholinergic

    An anticholinergic agent is a substance that blocks the neurotransmitter acetylcholine in the central nervous system and the peripheral nervous system....
     drugs may cause photophobia by paralyzing the iris sphincter muscle
    Iris sphincter muscle

    The Iris sphincter muscle is a muscle in the part of the eye called the iris. It encircles the eye, appropriate to its function as a constrictor....
    .
  • Hangover
    Hangover

    A hangover describes the sum of unpleasant physiological effects following heavy consumption of drugs, particularly alcoholic beverages. The most commonly reported characteristics of a hangover include headache, nausea, sensitivity to photophobia and phonophobia, lethargy, dysphoria, and thirst....
  • Chikungunya
    Chikungunya

    Chikungunya virus is an arbovirus, of the genus, Alphavirus, that is transmitted to humans by virus-carrying Aedes mosquitoes.or=de Lamballerie X, Leroy E, Charrel RN, Ttsetsarkin K, Higgs S, Gould EA...
  • Rabies
    Rabies

    Rabies is a virus zoonotic neurotropic virus disease that causes acute encephalitis in mammals. It is most commonly caused by a bite from an infected animal, but occasionally by other forms of contact....
  • Asperger's Syndrome and Autism
    Autism

    Autism is a Neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior....
  • Achromatopsia
    Achromatopsia

    Achromatopsia , is a medical syndrome that exhibits symptoms relating to at least five separate individual diseases. Although the term may refer to acquired disorders such as color agnosia and cerebral achromatopsia, it typically refers to an autosomal recessive congenital color vision disorder, the inability to perceive color AND to achieve...
  • Dyslexia
    Dyslexia

    Dyslexia is a learning disability that manifests itself primarily as a difficulty with Writing, particularly with Reading . It is separate and distinct from reading difficulties resulting from other causes, such as a non-neurological deficiency with vision or hearing, or from poor or inadequate reading instruction....


In mythology

In folklore
Folklore

Folklore is the body of expressive culture, including tales, music, dance, legends, oral history, proverbs, jokes, superstitions, customs, and so forth within a particular population comprising the traditions of that culture, subculture, or group ....
 and mythology
Mythology

The word mythology refers to a body of folklore/myths/legends that a particular culture believes to be true and that often use the supernatural to interpret natural events and to explain the nature of the universe and humanity....
, many creatures suffer from photophobia — or heliophobia
Heliophobia

Heliophobia has two meanings:* a specific phobia: dread or avoidance of sunlight* excessive sensitivity to sunlight....
, a specific fear of sunlight.

  • Vampires are said to be killed by sunlight.
  • Some of the many forms of Norse
    Norse mythology

    Norse, Viking or Scandinavian mythology comprises the beliefs, myths and legends of the Norse paganism of the North Germanic language people, including those who settled on Faroe Islands and Iceland, where most of the written sources for Norse mythology were assembled....
     troll
    Troll

    A troll is a fearsome member of a race of creatures from Norse mythology. Originally more or less the Nordic equivalents of giant , although often smaller in size, the different depictions have come to range from the fiendish giants ? similar to the ogres of England ? to a devious, more human-like folk of the wilderness, living underground...
    s     are said to either turn to stone or become trapped above ground when the sun rises.
  • C. S. Lewis
    C. S. Lewis

    Clive Staples Lewis , commonly referred to as C. S. Lewis and known to his friends and family as Jack, was an academic, medievalist, literary critic, essayist, lay theologian and Christian apologist....
     wrote that the alchemist Paracelsus
    Paracelsus

    Paracelsus was a Medieval physician, botanist, alchemy, astrologer, and general occultist. Born Phillip von Hohenheim, he later took up the name Philippus Theophrastus Aureolus Bombastus von Hohenheim, and still later took the title Paracelsus, meaning "equal to or greater than Celsus", a Roman encyclopedist, Aulus Cornelius Celsus fro...
     believed that gnome
    Gnome

    A gnome is a mythical creature characterized by its extremely small size and wiktionary:subterranean lifestyle. The word gnome is derived from the New Latin gnomus....
    s     explode when they go above ground: "if he thrust out his face ... [it] would break into splinters, bursting as a man would burst in interstellar space" — though in fact, humans exposed to the vacuum of space experience no such spectacular effect
    Explosive decompression

    Uncontrolled decompression refers to an unexpected drop in the pressure of a sealed system. Where the speed of the decompression occurs faster than air can escape from the lungs, this is known as explosive decompression , and is associated with explosion violence....
    .
  • In English folklore
    English folklore

    English folklore is the folk tradition which has developed in England over a number of centuries. Some stories can be traced back to their roots, while the origin of others is uncertain or disputed....
    , goblin
    Goblin

    A goblin is an imaginary evil, crabby, and mischievous creature described as a grotesquely disfigured or gnome-like Wiktionary:phantom, that may range in height from that of a dwarf to that of a human....
    s     are said to find light unbearable.
  • In Lithuanian
    Lithuanian mythology

    Lithuanian mythology is an example of paganism mythology containing archaic elements, developed by Lithuanians throughout the centuries....
     and some other Eastern European folklore, the devil
    Devil

    The Devil is the title given to the supernatural being, who, in mainstream Christianity, Islam, and some other religions, is believed to be a powerful, evil entity and the tempter of humankind....
     is said to go back to hell whenever the sun rises.


In fiction

  • A modern tradition has it that vampire
    Vampire

    Vampires are mythology or folklore Revenant who subsist by feeding on the blood of the living. In folkloric tales, the undead vampires often visited loved ones and caused mischief or deaths in the neighbourhoods they inhabited when they were alive....
    s burn and/or disintegrate when exposed to light; this tradition was in fact introduced in the 1922
    1922 in film

    Events* November 26 - The Toll of the Sea, starring Anna May Wong and Kenneth Harlan, debuts as the first general release film to use two-tone Technicolor ....
     film Nosferatu. (See the article on Nosferatu for more information.)
  • In J.R.R. Tolkien's works, goblins are said to get wobbly legs and become giddy in the head when outside, while trolls turn to stone.
  • In Lemony Snicket
    Lemony Snicket

    Lemony Snicket is a pseudonym used by author Daniel Handler in his book series A Series of Unfortunate Events, as well as a character in that series....
    's A Series of Unfortunate Events
    A Series of Unfortunate Events

    A Series of Unfortunate Events is a Children's literature book series of thirteen novels written by Lemony Snicket, and illustrated by Brett Helquist....
    , the zombies from the movie Zombies in the Snow
    Zombies in the Snow

    Zombies in the Snow is a fictional film presented as the last movie created by the fictional film director Dr. Gustav Sebald before his death in the children's novel series, A Series of Unfortunate Events, by Lemony Snicket ....
     are forced to retreat during daylit hours.
  • In the films Gremlins
    Gremlins

    Gremlins is an Cinema of the United States comedy horror film directed by Joe Dante and released in 1984 in film by Warner Bros. It is about a young man who receives a strange creature named Gizmo as a pet, which then spawns other creatures who transform into small, destructive, evil monsters....
     and Gremlins 2: The New Batch
    Gremlins 2: The New Batch

    Gremlins 2: The New Batch is a 1990 in film Cinema of the United States comedy horror film, and a sequel to Gremlins . It was directed by Joe Dante and written by Charles S....
    , both the Mogwai
    Mogwai (Gremlins)

    As depicted in the 1984 Joe Dante film Gremlins and its 1990 sequel ...
     and Gremlins are incredibly sensitive to bright light; direct sunlight on their skin will kill them in a matter of seconds.
  • A character from the anime
    Anime

    is animation in Japan and considered to be "Japanese animation" in the rest of the world. Anime dates from about 1917.Anime, in addition to manga , is extremely popular in Japan and well known throughout the world....
     Ouran High School Host Club
    Ouran High School Host Club

    is a manga series by Bisco Hatori, serialized in Hakusensha's LaLa magazine since August 5, 2003. The series follows Haruhi Fujioka, a scholarship student at Ouran High School, and the other members of the titular host club....
    , Umehito Nekozawa, avoids light, and wears a hood all the time to protect himself from it. When exposed to light for a short time, he collapses, but he eventually gets over it. Ironically his little sister, Kirimi, is afraid of darkness.
  • prot (lowercase is proper) from the planet K-PAX
    K-PAX

    K-PAX is the name of the first novel in the K-PAX series by Gene Brewer and a film based on the series:*K-PAX **K-PAX — film...
     (uppercase is proper) wears dark glasses while on our planet because he can see ultraviolet light and would be blind without them.
  • In the films Pitch Black
    Pitch Black

    Pitch Black is a 2000 in film science fiction action film film director by David Twohy.In the film, a dangerous criminal is being transported to prison in a cargo spacecraft....
     and The Chronicles of Riddick
    The Chronicles of Riddick

    The Chronicles of Riddick is a 2004 in film Cinema of the United States science fiction film / fantasy film / Thriller film. It follows the adventures of Riddick, as he attempts to elude capture after the events depicted in the 2000 in film film Pitch Black ....
    , the antihero protagonist Richard B. Riddick is photophobic as a result of medical alterations to his eyes which give him superhuman night vision
    Night vision

    Night vision is the ability to see in a dark environment. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range....
    , but force him to wear welding goggles in the light.
  • In Scott Westerfeld's Midnighters Trilogy
    Midnighters Trilogy

    The Midnighters Trilogy, is a science-fiction fantasy series written by Scott Westerfeld. It was published by Eos in 2004. It is comprised of three books; The Secret Hour, Touching Darkness and Blue Noon....
    , all the midnighters (except Jessica Day) are photophobic and have an aversion to sunlight.
  • The Zombies in the book and film I am Legend
    I Am Legend

    I Am Legend is a 1954 science fiction/horror fiction novel by Richard Matheson about the last man alive in Los Angeles. It was influential on the developing modern Vampires in popular culture as well as the Zombies in popular culture, in popularizing the concept of a worldwide apocalypse due to disease, and in exploring the notion of vamp...
     have a strong aversion to sunlight. As direct exposure to ultraviolet radiation burned their skin.
  • In the film Star Trek: Nemesis
    Star Trek: Nemesis

    Star Trek Nemesis is the tenth feature film based on the Star Trek television series. It is the fourth and last film to star the cast from Star Trek: The Next Generation....
    , the Reman
    Reman

    In the fictional Star Trek universe, Remans are natives of the planet Romulus and Remus , resembling Bat. They were first introduced in the movie Star Trek Nemesis....
    s have lived on the dark side of Remus due to the scorching temperatures on the light side of their tidally-locked planet. Because of this, they are all photophobes.


See also

  • Heliophobia
    Heliophobia

    Heliophobia has two meanings:* a specific phobia: dread or avoidance of sunlight* excessive sensitivity to sunlight....
    , fear of sunlight
  • Photosensitivity
    Photosensitivity

    Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light....
    , the amount to which an object reacts upon receiving photons of light
  • Erythropoietic protoporphyria
    Erythropoietic protoporphyria

    Erythropoietic protoporphyria is a relatively mild form of porphyria, although very painful, which arises from a deficiency in the enzyme ferrochelatase, leading to abnormally high levels of protoporphyrin in the tissue....
    , a disease manifesting itself with painful photosensitivity
    • Photic sneeze reflex
      Photic sneeze reflex

      Photic sneeze reflex is a genetics autosomal dominant trait, which causes sneeze when exposed suddenly to bright light, possibly many times consecutively....
      , a medical condition by which people exposed to bright light sneeze^


External links