A formulation of 10 mg lutein and 2 mg zeaxanthin has been shown to reduce the risk of age-related macular degeneration progressing to advanced stages, although these carotenoids have not been shown to prevent the disease. There is some evidence that these carotenoids protect the pigmented region from some types of macular degeneration. Zeaxanthin predominates at the macula, while lutein predominates elsewhere in the retina. The yellow color comes from its content of lutein and zeaxanthin, which are yellow xanthophyll carotenoids, derived from the diet. The retina's receptor layer contains two types of photosensitive cells, the rod cells and the cone cells.īecause the macula is yellow in color, it absorbs excess blue and ultraviolet light that enter the eye and acts as a natural sunblock (analogous to sunglasses) for this area of the retina. It is a small pit that contains the largest concentration of cone cells. The fovea is located near the center of the macula. The umbo is the center of the foveola which in turn is located at the center of the fovea. The anatomical macula is defined histologically in terms of having two or more layers of ganglion cells. The clinical macula is seen when viewed from the pupil, as in ophthalmoscopy or retinal photography. The anatomical macula at 5.5 mm (0.22 in) is much larger than the clinical macula which, at 1.5 mm (0.059 in), corresponds to the anatomical fovea. Īn even smaller central region of highest receptor density (40–80 μm) is sometimes referred to as the foveal bouquet. The macula in humans has a diameter of around 5.5 mm (0.22 in) and is subdivided into the umbo, foveola, foveal avascular zone, fovea, parafovea, and perifovea areas. Its center is shifted slightly away from the optical axis (laterally, by 5°=1.5 mm). The macula is an oval-shaped pigmented area in the center of the retina of the human eye and other animal eyes. Structure Photograph of the retina of the human eye, with overlay diagrams showing the positions and sizes of the macula, fovea, and optic disc Schematic diagram of the macula lutea of the retina, showing perifovea, parafovea, fovea, and clinical macula The term macula lutea comes from Latin macula, "spot", and lutea, "yellow". The macula is responsible for the central, high-resolution, color vision that is possible in good light and this kind of vision is impaired if the macula is damaged, for example in macular degeneration. The anatomical macula at a size of 5.5 mm (0.22 in) is much larger than the clinical macula which, at a size of 1.5 mm (0.059 in), corresponds to the anatomical fovea. The macula (/ˈmakjʊlə/) or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals.
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