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  1. 1
    JMdict
    anatomy macula;macula lutea;yellow spot
  2. 2
    Wikipedia

    The macula or macula lutea (from Latin macula, "spot" + lutea, "yellow") is an oval-shaped pigmented area near the center of the retina of the human eye. It has a diameter of around 5.5 mm (0.22 in). The macula is subdivided into the umbo, foveola, foveal avascular zone (FAZ), fovea, parafovea, and perifovea areas. After death or enucleation (removal of the eye) the macula appears yellow, a color that is not visible in the living eye except when viewed with light from which red has been filtered. 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. The clinical macula is seen when viewed from the pupil, as in ophthalmoscopy or retinal photography. The anatomical macula is defined histologically in terms of having two or more layers of ganglion cells. The umbo is the center of the foveola which in turn is located at the centre of the fovea. The fovea is located near the center of the macula. It is a small pit that contains the largest concentration of cone cells. The retina contains two types of photosensitive cells, the rod cells and the cones. The normal human eye contains three different types of cone, with different ranges of spectral sensitivity; hence the cones enable us to distinguish different colors. There is only one type of rod, but the rods are more sensitive than the cones, so in dim light we rely on them and do not discriminate colors. In the fovea centralis or macula lutea or simple yellow spot, cones predominate and are present at high density. The macula is thus 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.

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