The Macula Anatomy, Physiology and
Pathology of the Human Eye
Ted M. Montgomery,
Optometric Physician Click on a selection here fovea centralis color vision color deficiency color vision testing macular degeneration Amsler grid cystoid macular edema central serous retinopathy , or scroll down the page.
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The macula lutea is the small, yellowish central portion of the retina , and it is the area providing the clearest, most distinct vision. When one looks directly at something, the light from that object forms an image on ones macula. A healthy macula ordinarily is capable of achieving at least 20/20 (normal) vision or visual acuity, even if this is with a correction in glasses or contact lenses. Not uncommonly, an eyes best visual acuity is 20/15; in this case, that eye can perceive the same detail at 20 feet that a 20/20 eye must move up to 15 feet to see as distinctly. Some people are even capable of 20/10 vision, which is twice as good as 20/20. Vision this acute may be due to there being more cones per square millimeter of the macula than in the average eye, enabling that eye to distinguish much greater detail. fovea centralis The very center of the macula is called the fovea centralis , an area where all of the photoreceptors are cones ; there are no rods in the fovea. The fovea is the point of sharpest, most acute visual acuity. (The center of the fovea is the foveola.) Because the fovea has no rods, small dim objects in the dark cannot be seen if one looks directly at them. For this reason, to detect faint stars in the sky, one must look just to the side of them so that their light falls on a retinal area, containing numerous rods, outside of the macular zone. | |
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