The symmetry of our visual apparatus as a dual organ : a plea to modify the customary notation of the ocular meridians / Herman Knapp.

  • Knapp, Herman, 1832-1911.
Date:
[1902]
Catalogue details

Licence: In copyright

Credit: The symmetry of our visual apparatus as a dual organ : a plea to modify the customary notation of the ocular meridians / Herman Knapp. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    V E ' r\_ - *&. i <i THE SYMMETRY OF OUR VISUAL APPARATUS AS A DUAL ORGAN. A PLEA TO MODIFY THE CUSTOMARY NOTATION OF THE OCULAR MERIDIANS.* Our visual apparatus is a dual (paired) organ, sym- metrically placed on both sides of the median plane of the body. In the skull the dual parts coalesce at two places, the chiasm and the quadrigeminal bodies which are cut by the median plane, whereas in all other places the dual parts are so arranged that each of their points on one side has a corresponding point at equal distance on the other, as if one side were a reflex image of the other, cast by a plain mirror substituting the median plane of the body. Outside the skull, all the remaining parts, orbits and their contents, as well as the eyeballs with all their in- tricate structures, follow the same rule; each point has its correspondent at the same distance on the other side of the median plane of the head. My purpose, at this place, is to consider only one part of our visual organ with regard to the law of symmetry, the refractive apparatus. A complete analysis of the final refractive effect would require the determination of the curvature of the anterior surface of the cornea, the curvature and position of the surfaces, as well as the co- efficient of refraction of the lens, and lastly, the inclina- tion of the cornea and lens toward the optical axis of the eye, i. e., the centration of the refractive system. It is well known that the anterior surface of the * Read at the Fifty-third Annual Meeting of the American Medical Association, in the Section on Ophthalmology, and ap- proved for publication by the Executive Committee: Drs. Frank Allport, H. V. Wiirdemann and J. A. Lippincott. HERMAN KNAPP, M.D. NEW YORK CITY.