Phosphene
Phosphene
Phosphene (/ˈfɒsfɪn/; from the Greek words phos (light) and phainein (to show)) is a phenomenon characterized by the experience of seeing light without light actually entering the eye. The term is used to describe the perception of light caused by external pressure on the eye or direct stimulation of the visual system other than by light.
Etymology
The term "phosphene" comes from the Greek words phos (light) and phainein (to show). It was first used in the 19th century to describe the phenomenon of seeing light without any light actually entering the eye.
Causes
Phosphenes can be directly induced by mechanical, electrical, or magnetic stimulation of the retina or visual cortex as well as by random firing of cells in the visual system. They have also been reported as a side effect of electroconvulsive therapy, brain surgery, and high altitude climbing without oxygen.
Related Terms
- Entoptic Phenomenon: Visual effects whose source is within the eye itself. Phosphenes are a type of entoptic phenomenon.
- Afterimage: An image that continues to appear in the eyes after a period of exposure to the original image. Phosphenes can appear as afterimages.
- Visual Snow: A condition resulting in a snow or television-like static in parts or the whole of the visual field. Phosphenes can be a symptom of visual snow.
See Also
References
External links
- Medical encyclopedia article on Phosphene
- Wikipedia's article - Phosphene
This WikiMD dictionary article is a stub. You can help make it a full article.
Languages: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
Urdu,
বাংলা,
తెలుగు,
தமிழ்,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
European
español,
Deutsch,
français,
русский,
português do Brasil,
Italian,
polski