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Color or colour is the visual perception based on the electromagnetic spectrum. Though color is not an inherent property of matter, color perception is related to an object's light absorption, reflection, emission spectra and interference. For most humans, color are perceived in the visible light spectrum with three types of cone cells (trichromacy). Other animals may have a different number of cone cell types or have eyes sensitive to different wavelength, such as bees that can distinguish ultraviolet, and thus has a different color sensitivity range. Animal perception of color originates from different light wavelength or spectral sensitivity in cone cell types, which is then processed by the brain.
Color blindness or color vision deficiency (CVD) is the decreased ability to see color or differences in color. It can impair tasks such as selecting ripe fruit, choosing clothing, and reading traffic lights. Color blindness may make some academic activities more difficult. However, issues are generally minor, and the colorblind automatically develop adaptations and coping mechanisms. People with total color blindness (achromatopsia) may also be uncomfortable in bright environments and have decreased visual acuity.
Digitalis is a genus of about 20 species of herbaceous perennial plants, shrubs, and biennials, commonly called foxgloves.
Complementary colors are pairs of colors which, when combined or mixed, cancel each other out by producing a grayscale color like white or black. When placed next to each other, they create the strongest contrast for those two colors. Complementary colors may also be called "opposite colors".
Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical sensitivity of the eyes, though the term is sometimes additionally applied to abnormal or irrational fear of light such as heliophobia. The term photophobia comes from the Greek φῶς (phōs), meaning "light", and φόβος (phóbos), meaning "fear".
Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye's iris and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris.
Subconjunctival bleeding, also known as subconjunctival hemorrhage or subconjunctival haemorrhage, is bleeding from a small blood vessel over the whites of the eye. It results in a red spot in the white of the eye. There is generally little to no pain and vision is not affected. Generally only one eye is affected.
The Purkinje effect or Purkinje phenomenon is the tendency for the peak luminance sensitivity of the eye to shift toward the blue end of the color spectrum at low illumination levels as part of dark adaptation. In consequence, reds will appear darker relative to other colors as light levels decrease. The effect is named after the Czech anatomist Jan Evangelista Purkyně. While the effect is often described from the perspective of the human eye, it is well established in a number of animals under the same name to describe the general shifting of spectral sensitivity due to pooling of rod and cone output signals as a part of dark/light adaptation.
Fall of Leaves , or Falling Autumn Leaves is a pair of paintings by the Dutch painter Vincent van Gogh. They were executed during the two months at the end of 1888 that his artist friend Paul Gauguin spent with him at The Yellow House in Arles, France.
Santonin is a drug which was widely used in the past as an anthelminthic. It is an organic compound consisting of colorless flat prisms, turning slightly yellow from the action of light and soluble in alcohol, chloroform and boiling water.
There is no consensus on Vincent van Gogh's health. His death in 1890 is generally accepted to have been a suicide. Many competing hypotheses have been advanced as to possible medical conditions from which he may have suffered. These include epilepsy, bipolar disorder, borderline personality disorder, sunstroke, acute intermittent porphyria, lead poisoning, Ménière's disease, schizophrenia, schizoaffective disorder, substance use disorder, non-suicidal self-injury disorder ("self-harm"), and a possible anxiety disorder.
Cyanopsia is a medical term for seeing everything tinted with blue. It is also referred to as blue vision. Cyanopsia often occurs for a few days, weeks, or months after removal of a cataract from the eye. Cyanopsia also sometimes occurs as a side effect of taking sildenafil, tadalafil, or vardenafil.
Vincent van Gogh made many copies of other people's work between 1887 and early 1890, which can be considered appropriation art. While at Saint-Paul asylum in Saint-Rémy-de-Provence, France, where Van Gogh admitted himself, he strived to have subjects during the cold winter months. Seeking to be reinvigorated artistically, Van Gogh did more than 30 copies of works by some of his favorite artists. About twenty-one of the works were copies after, or inspired by, Jean-François Millet. Rather than replicate, Van Gogh sought to translate the subjects and composition through his perspective, color, and technique. Spiritual meaning and emotional comfort were expressed through symbolism and color. His brother Theo van Gogh would call the pieces in the series some of his best work.
Lecithin cholesterol acyltransferase deficiency is a disorder of lipoprotein metabolism. The disease has two forms: Familial LCAT deficiency, in which there is complete LCAT deficiency, and Fish-eye disease, in which there is a partial deficiency.
Oleandrin is a cardiac glycoside found in the poisonous plant oleander. As a main phytochemical of oleander, oleandrin is associated with the toxicity of oleander sap, and has similar properties to digoxin.
Girl in White was painted by Vincent van Gogh in 1890 in Auvers-sur-Oise, France, during the last months of his life. Girl in White has been part of the Chester Dale Collection in the National Gallery of Art, Washington D.C. since 1963.
Saint-Paul Asylum, Saint-Rémy is a collection of paintings that Vincent van Gogh made when he was a self-admitted patient at the Saint-Paul asylum in Saint-Rémy-de-Provence, since renamed the Clinique Van Gogh, from May 1889 until May 1890. During much of his stay there he was confined to the grounds of the asylum, and he made paintings of the garden, the enclosed wheat field that he could see outside his room and a few portraits of individuals at the asylum. During his stay at Saint-Paul asylum, Van Gogh experienced periods of illness when he could not paint. When he was able to resume, painting provided solace and meaning for him. Nature seemed especially meaningful to him, trees, the landscape, even caterpillars as representative of the opportunity for transformation and budding flowers symbolizing the cycle of life. One of the more recognizable works of this period is The Irises. Works of the interior of the hospital convey the isolation and sadness that he felt. From the window of his cell he saw an enclosed wheat field, the subject of many paintings made from his room. He was able to make but a few portraits while at Saint-Paul.
Landscape at Auvers in the Rain is an oil on canvas painting by the Dutch Post-Impressionist painter Vincent van Gogh.
Color blind glasses or color correcting lenses are light filters, usually in the form of glasses or contact lenses, that attempt to alleviate color blindness, by bringing deficient color vision closer to normal color vision or to make certain color tasks easier to accomplish. Despite viral status, the academic literature is generally skeptical of the efficacy of color correcting lenses.
References
- ↑ "Vincent van Gogh". Psych.ucalgary.ca. Retrieved 2015-07-09.
- ↑ Weatherall, D. J.; Ledingham, J. G. G.; Warrell, D. A. (1996). Oxford Textbook of Medicine . 3rd ed. Oxford: Oxford University Press. 2055.
