Name = Photophobia
DiseasesDB = 24599
ICD10 = ICD10|H|53|1|h|53
ICD9 = ICD9|368.13
MedlinePlus = 003041
MeshID = D020795
Photophobia is a
symptomof excessive sensitivity to lightand the aversion to sunlightor 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
photoreceptors in the retinaand subsequent excessive electric impulses to the optic nerve. 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).
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.
Patients may develop photophobia as a result of several different medical conditions, related to the
eyeor the nervous system.
Eyedisease, injury, or infection such as chalazion, episcleritis, glaucoma, keratoconus
*Burns to the
Dilation(naturally or chemically induced)
Anticholinergicdrugs may cause photophobia by paralyzing the iris sphincter muscle.
Asperger's Syndromeand Autism
folkloreand mythology, many creatures suffer from photophobia — or heliophobia, a specific fear of sunlight.
* Some of the many forms of Norse
trolls are said to either turn to stone or become trapped above ground when the sun rises.
C. S. Lewiswrote [ C. S. Lewis, [http://books.google.com/books?id=rW4GiB5dFu4C&pg=PA9&sig=HPf9pTcnA6zU9Y-Bagoh3FbSUF4 "The True Nature of Gnomes"] . In "Poems".] that the alchemist Paracelsusbelieved that gnomes 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.
English folklore, goblins are saidwho to find light unbearable.
* In Lithuanian and some other Eastern European folklore, the
devilis said to go back to hell whenever the sun rises.
* A modern tradition has it that
vampires burn and/or disintegrate when exposed to light; this tradition was in fact introduced in the 1922 film " Nosferatu". (See the article on " Nosferatu" for more information.)
J.R.R. Tolkien's works, goblinsare said to get wobbly legs and become giddy in the head when outside, while trolls turn to stone.
Lemony Snicket's " A Series of Unfortunate Events", the zombies from the movie " Zombies in the Snow" are forced to retreat during daylit hours.
* In the films "
Gremlins" and "", both the Mogwaiand 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" Ouran High School 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(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" and " The Chronicles of Riddick", the antihero protagonist Richard B. Riddickis photophobic as a result of medical alterations to his eyes which give him superhuman night vision, but force him to wear welding goggles in the light.
Scott Westerfeld's Midnighterstrilogy, all the midnighters (except Jessica Day) are photophobic and have an aversion to sunlight.
Heliophobia, fear of sunlight
Photosensitivity, the amount to which an object reacts upon receiving photons of light
Erythropoietic protoporphyria, a disease manifesting itself with painful photosensitivity
Photic sneeze reflex, a medical condition by which people exposed to bright light sneeze^
Lewis, C.S. "Poems: C.S. Lewis". U.S.: Harvest/HBJ, 1964. ISBN 0-15-672248-8.
* [http://www.allaboutvision.com/conditions/lightsensitive.htm Photophobia (Light Sensitivity) at allaboutvision.com]
* [http://www.photophobia.tk www.photophobia.tk]
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