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Image from page 84 of “The commoner diseases of the eye : how to detect and how to treat them” (1904)

Image from page 84 of “The commoner diseases of the eye : how to detect and how to treat them” (1904)
Eyes Vision
Identifier: commonerdiseases00woodrich
Title: The commoner diseases of the eye : how to detect and how to treat them
Year: 1904 (1900s)
Authors: Wood, Casey Albert, 1856- Woodruff, Thomas Adams
Subjects: Eye — Diseases and defects
Publisher: Chicago : G.P. Engelhard & Company
Contributing Library: University of California Libraries
Digitizing Sponsor: Internet Archive

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Text Appearing Before Image:
Mixed Astigmatism. V, Rays in Vertical Meri-dian Focusing in Front of Retina; H, Rays inHorizontal Meridian Focusing BehindRetina. Inasmuch as the majority of the forms of as-tigmatism arc due to the abnormal shape of tin-eyeball it is usually congenital, but in some in-stances (after operation, injury, etc.) it may beacquired. Astigmatism may be detected and itsamount accurately measured bv a number oi THE NORMAL AND ABNORMAL EYE ?y objective means, as set forth in the followingchapter. A valuable subjective test for thepresence of this defect is the astigmatic chart,one form of which is pictured in the text.It is sufficient for the patient to look, with eacheye separately, at the figures on the chart. If

Text Appearing After Image:
Test Figures for Detecting the Presence of Astig-matism. astigmatism be present one or more of themwill appear more blurred (or more distinct)than the others. Astigmatism generally produces discomfort 80 COMMONER DISEASES OK THE EYE when the patient attempts to use the eyes forreading, sewing, or other forms of near work.All the symptoms met with in eye-strain due tohypermetropia or myopia are more or less ag-gravated by the addition of astigmatism, evenof low degree, especially if the patient be in apoor state of health and of a neurasthenic dis-position. Distant as well as near vision mayalso be materially interfered with and rendereddecidedly uncomfortable. Astigmatism should be corrected with acylindrical glass either alone (in simple astig-matism) or in combination with a sphericallens in compound or mixed astigmatism. Theaxis of the cylinder is placed in the meridian ofgreater corneal curvature in hypermetropicastigmatism and lesser corneal curvature inmyopic astigmatism, i. c,

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