Binocular astigmatism / [by H. Culbertson].

  • Culbertson, H. (Howard), 1828-1890.
Date:
[1888]
Catalogue details

Licence: Public Domain Mark

Credit: Binocular astigmatism / [by H. Culbertson]. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    BINOCUI.AR ASTIGMATISM. Reprinted from the Journal of the American Medical I have not infrequently encountered cases of astigmatism in which, after having corrected the error in each eye separately, and on testing both eyes simultaneously, in binocular vision, have found that vision proximum was not perfect, and in order to attain normal vision near at hand, in binocular sight, the angle denoting the axis of the cylindrical glass must be changed in one or both eyes. In correcting this binocular defect, types and the astigmatic bars were employed. If the patient looks upon the floor it will seem to incline to the right or left, and on changing the axis of one or both cylinders, the surface will appear level. But the same defect will be apparent if a board 12x3 inches, with parallel sides, be held in front of the patient at one metre, and on a level with the eyes. In these cases then, the answer will be, that the right or left end of said object-board is wider than the other. The angle of one or both cylinders is changed until each end of the object- board seems equally wide, or in other words, the sides are parallel; and then it will be found that the astigmatic bars are seen normally in near or far vision, in binocular vision. All of my refrac- tion cases are estimated, not only by the usual methods, but the test as given is applied to all