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Leukodystrophies are a group of, usually, inherited disorders, characterized by degeneration of the white matter in the brain. [ 1 ] The word leukodystrophy comes from the Greek roots leuko, "white", dys, "abnormal" and troph, "growth". The leukodystrophies are caused by imperfect growth or development of the glial cells which produce the ...
Xanthopsia is a color vision deficiency in which there is a dominantly yellow bias in vision due to a yellowing of the optical media of the eye. The most common causes are digoxin 's inhibitory action on the sodium pump, and the development of cataracts which can cause a yellow filtering effect. It has been suggested that Van Gogh contracted ...
The irises of human eyes exhibit a wide spectrum of colours. Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye 's iris [ 1 ][ 2 ] and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris. [ 3 ]: 9. In humans, the pigmentation of the iris varies from ...
The four pigments in a bird's cone cells (in this example, estrildid finches) extend the range of color vision into the ultraviolet. [1]Tetrachromacy (from Greek tetra, meaning "four" and chroma, meaning "color") is the condition of possessing four independent channels for conveying color information, or possessing four types of cone cell in the eye.
Lipofuscin. Lipofuscin is the name given to fine yellow-brown pigment granules composed of lipid -containing residues of lysosomal digestion. [ 1 ][ 2 ] It is considered to be one of the aging or "wear-and-tear" pigments, found in the liver, kidney, heart muscle, retina, adrenals, nerve cells, and ganglion cells. [ 3 ]
Historically from Stargardt's first description of his eponymous disease until recently, the diagnosis was based on looking at the phenotype using examination and investigation of the eye. Since the advent of genetic testing, the picture has become more complex. What was thought to be one disease is, in fact, probably at least three different ...
Prognosis. fatal. Frequency. 1 in 40,000 births. Metachromatic leukodystrophy (MLD) is a lysosomal storage disease which is commonly listed in the family of leukodystrophies as well as among the sphingolipidoses as it affects the metabolism of sphingolipids.
Colors of confusion include blue/purple and green/yellow. [2] Deuteranopia is a severe form of red-green color blindness, in which the M-cone is absent. It is sex-linked and affects about 1% of males. Color vision is very similar to protanopia. [2] Tritanopia is a severe form of blue-yellow color blindness, in which the S-cone is absent. It is ...