The clinical use of prisms : and the decentering of lenses / by Ernest E. Maddox.

  • Maddox, Ernest E. (Ernest Edmund), 1860-1933.
Date:
1907
Catalogue details

Licence: In copyright

Credit: The clinical use of prisms : and the decentering of lenses / by Ernest E. Maddox. Source: Wellcome Collection.

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

    27/230 (page 11)
    Does this little anomaly introduce any difficulty in the true setting of an oval prism ? The answer is. Not if we employ any optical method of ascertaining the true base-apex line, nor yet if we use such an instrument as the prism measure of the Geneva Optical Company (Fig. 2). On placing any oval prism under its teeth and rotating the prism until the index records its maximum excursion, the teeth lie on the line A B, or on one parallel to it, thus indicating the direction of the true optical base-apex line, which is, of course, A B, and not a b.