Page:  of 52323
 

FARSIGHTEDNESS

or hyperopia, 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 eye 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 eyeglasses with convex lenses compensate for the refractive errors.

____________________

The Columbia Encyclopedia, Sixth Edition Copyright© 2004, Columbia University Press. Licensed from Lernout & Hauspie Speech Products N.V. All rights reserved.

-16538-

Questia Media America, Inc. www.questia.com

Publication Information: Encyclopedia Article Title: Farsightedness. Encyclopedia Title: The Columbia Encyclopedia, Sixth Edition. Publisher: Columbia University Press. Place of Publication: New York. Publication Year: 2004.
This feature allows you to create and manage separate folders for your different research projects. To view markups for a different project, make that project your current project.
This feature allows you to save a link to the publication you are reading or view all the publications you have put on your bookshelf.
This feature allows you to save a link to the page you are reading, which you can later return to from Projects.
This feature allows you to highlight words or phrases on the publication page you are reading.
This feature allows you to save a note you write on the publication page you are reading.
This feature allows you to create a citation to the page you are reading that you can paste into your paper. Highlight a passage to include that passage as a quotation.
This feature allows you to save a reference to a publication you are reading for your bibliography or generate a bibliography you can paste into your paper.
This feature allows you to print a range of pages or a single page from the item you are reading, including your notes or highlights (IE users must have "print background colors and image" setting selected.)
This feature allows you to look up words in a dictionary, thesaurus or encyclopedia.
  About Questia Tools
Close Window  
Questia's powerful research tools allow you to highlight, take notes, bookmark and even create instant citations and bibliographies. To use these features and save hours of work, you must be a subscriber to the Questia service.
Need a Questia account?
Choose a subscription plan to save tons of time, stress and hassle, and experience faster, easier research.

» Click here for our subscription plans

Already have a Questia account? Login now!
Error
Working...
Choose one of the options for printing:
Print this page (No Charge)
Print pages to *
Print pages to *
Quick Print Center
View Shopping Cart
*charges may apply