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condition in which far objects can be seen easily but there is difficulty in near vision. It is caused by a defect of refraction in which the image is focused behind the retina of the eyeeye,
organ of vision and light perception. In humans the eye is of the camera type, with an iris diaphragm and variable focusing, or accommodation. Other types of eye are the simple eye, found in many invertebrates, and the compound eye, found in insects and many other
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 rather than upon it, either because the eyeball is too short or because the refractive power of the lens is too weak. Presbyopia, a similarly faulty vision, is attributable to physiological changes in the lens brought on by age. Corrective eyeglasseseyeglasses
or spectacles,
instrument or device for aiding and correcting defective sight. Eyeglasses usually consist of a pair of lenses mounted in a frame to hold them in position before the eyes.
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 with convex lenses compensate for the refractive errors.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(hyperopia), a deviation from normal refraction in the eye wherein parallel light rays, after refraction in the eye, are brought to a focus behind the retina and the retinal images as a result are diffuse and unclear.

Farsightedness is caused either by the fact that the refractive mediums of the eye (the cornea and the crystalline lens) refract light poorly (index hyperopia) or because the antero-posterior axis of the eye is too short (axial hyperopia); most often the two causes are found in combination. Farsightedness is found in the majority of newborns, but as the infant grows, the eyeball enlarges somewhat and the farsightedness usually disappears. The hyperopic eye, which is poorly suited for bringing parallel rays together at the retina, is even less capable of focusing divergent rays (that is, those from close objects). Thus, vision is poor both at distances and from up close, so that essentially the term “farsightedness” is not altogether accurate. With slight degrees of farsightedness, young people continually strain the so-called ciliary muscle, increasing the curvature of the crystalline lens; this increases the refractive capacity of the lens (accommodation), and clear vision may be attained. In the middle-aged and elderly this capacity for accommodation is weakened; so-called old-age farsightedness (presbyopia) develops, manifested in the efforts of the person to hold observed objects (for example, a book or newspaper) somewhat further from the eyes. Farsightedness may cause headaches; in children it may lead to the development of convergent strabismus. Correction of vision (compensation) for farsightedness is achieved by wearing eyeglasses with convex lenses; the strongest lens is chosen that will ensure the clearest vision. By increasing the refractive power of the eye, such a lens transfers the focus of the light rays to the retina.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
It is too early to recommend that all farsighted children get glasses, says Kulp, but she hopes this research, the first large-scale study to look at farsightedness and reading readiness in this age group, is an Important step In clearing up the uncertainty.
The study noted that in most children, farsightedness is mild and has little effect on vision.
Sheikh Faisal said the status achieved by Jordan as a result of playing a pivotal role in the region didn't come out of thin air; instead, it was the outcome of the statesmanship, farsightedness and the enlightened vision of His Majesty King Abdullah II.
African can learn from your strong will, powerful decisions and farsightedness," she added.
* Farsightedness, or hyperopia, is the opposite of nearsightedness.
"The conference will tackle the most recent treatments of the refraction of the eye including farsightedness - nearsightedness - astigmatism and the recent developments in third generation lasers which has become one of the most common solutions in the world to correct eye-sights problems".
NEW YORK (PAN): Observing that there could be no quick fixes to the current mess in Afghanistan, an eminent Afghan expert has recommended a six-point formula for the next US President and said finding a solution needs great wisdom, courage and farsightedness.
Your article states that farsightedness will be treated with these new electric lenses (Switch-a-Vision: Electric spectacles could aid aging eyes;' SN: 4/22/06, p.
Hyperopia: farsightedness, or the inability to bring nearby objects into focus (the image of such an object is focused as if it could come to a focus behind the retina).
Similar lenses are currently being tested for a wide range of refractive problems, including farsightedness and astigmatism.
Please, councillors, have the requisite farsightedness that will enable future generations to take pleasure in their surroundings just as our forefathers did for us.