Notebook, 1993-



Imperfect, Blurred, or Distorted optical system resulting in a blurred and imperfect image . . . . Inability to corneal irregularity [Cornea is a transparent film that covers the Iris and pupil and admits light to the interior]

R  E  F  E  R  E  N  C  E  S 
Astigmatism of the eye is due to a fault in the curvature of the cornea or lens. If either curved surface is not symmetrical, rays in different planes will not be focused at the same distance behind the lens. Thus part of the image will be out of focus. This defect can usually be corrected by wearing spectacles with cylindrical lenses instead of spherical ones . . . . Almost two out of three persons have at least a mild form of astigmatism. [p. 70]

Astigmatism n [1849] 1: a defect of an optical system [as a lens] causing rays from a point to fail to meet in a focal point resulting in a blurred and imperfect image 2: a defect of vision due to astigmatism of the refractive system of the eyes and esp. to corneal irregulaity 3: distorted understanding suggestive of the blurred vision of an astigmatic person

Astigmatic adj. [a- + Gk stigmat-, stgma stigma] [1849] 1: affected with, relating to, or correcting astigmatism 2: showing incapacity for observation or discrimation [an __ fanaticism, a disregard for the facts -N.Y. Herald Tribune]

[Merriam-Webster's Collegiate Dictionary, 10th Edition. Springfield, MA, USA: Merriam-Webster, Inc. 1995.]



The contents of this site, including all images and text, are for personal, educational, non-commercial use only.The contents of this site may not be reproduced in any form without proper reference to Text, Author, Publisher, and Date of Publication [and page #s when suitable].