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)

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    Trial cases are still often provided with a series of prisms, marked in the old way, from No. I or No. 2 up to No. 12 or No. 24, but since the author gave to Messrs. Curry & Paxton, in 1886, a means of measuring the deviating angle of prisms, they have been able to make them marked according to their deviation of light. Fig. 2.—Prism Measure : the index points to the required- angle when the teeth at its foot are pressed upon the prism. It is to the ophthalmic surgeon that a knowledge of the deviating angle is of advantage. To the optical workman, on the contrary, the refracting angle is the only important item. He may first