New truths in ophthalmology / as developed by G. C. Savage.

  • G. C. Savage
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: New truths in ophthalmology / as developed by G. C. Savage. Source: Wellcome Collection.

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    from astigmatism, and even in astigmatic eyes when the prin- cipal meridians are vertical and horizontal, the horizontal object and the retinal image are always in the same plane. In oblique astigmatism, be the obhquity much or little, it is a physical impossibility for the horizontal object and its reti- nal image to occupy the same plane. The same is true of all objects not in a plane with one or the other of the two RIGHT LEFT principal meridians. There is, therefore, not only blurring, but also obliquity of the image. Figure i represents a pair of eyes in which the two prin- cipal meridians are vertical and horizontal (they can also represent eyes that are non-astigmatic). If before these eyes an arrow, or the picture of an arrow, be held horizon- tally, the arrowhead toward the patient's left, it will throw a reversed image on each retina, and the two images will be in the same plane with the object. These two im-
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