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.

    16/288 page 4
    surface has the shorter focus; the least rapidly curved surface, the longer focus. As already defined, astigmatism is due to a want of simi- larity of curvature of the different parts of the cornea. Figure A is intended to represent an astigmatic eye. The continuous and dotted curved lines to the left represent the meridians of greatest and least curvature of the cornea. Figure A. known in ophthalmology as the two principal meridians. These must be considered as at right angles to each other. The continuous line, which is the more rapidly curved, we will consider as the vertical meridian of the cornea; and as such it is destined to refract the rays of light entering the eye in the vertical plane. The two continuous parallel hnes represent this plane of rays; and these, as shown in the figure, are so bent by this curved surface as to be brought to a fo- cus on the retina, represented by the continuous curved line I
    No text description is available for this image
    No text description is available for this image
    No text description is available for this image