A comparison of total and manifest hypermetropia, as determined by the the prisoptometer, with and without the use of mydriatics / by H. Culbertson.

  • Culbertson, H. (Howard), 1828-1890.
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: A comparison of total and manifest hypermetropia, as determined by the the prisoptometer, with and without the use of mydriatics / by H. Culbertson. 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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    There has been no creation of hypermetropia, which has simply diminished as manifest and increased as latent hy- peropia, and the reduction of the former has decreased as the power of the ciliary muscle is weakened, as the age ap- proaches 45 years. It is quite evident, too, that, while using the instrument to detect low degrees of hyperopia, the ciliary muscle does not relax, but, by its positive contraction, maintains and over- comes the manifestation of a portion of the hyperopia, so that only when this muscle is paralyzed can the total hy- peropia be obtained, up to 45 years of age. Before and including the latter age, the table reveals in these cases that there remained enough, or an excess, of ciliary power to maintain the diminishing hyperopia mani- festo present after the total H. had been deducted from the dioptrics of ciliary power present in each case, according to the age. This is shown in the following table: NO. OF CASE. Age, years. Ciliary power for the age, in dioptrics. Dioptrics of total H. Dioptrics, ex- cess of ciliary power. Dioptrics of flm. 2 12 13-00 5-00 D8-00 D5-00 3 12 13-00 6-00 D7-00 D6-00 4 15 12-00 0-15 11-25 D0-00 8 11 9-00 2-25 6-50 D2-50 18 24 8-50 6-50 2-00 Dl-75 33 33 5-50 1-25 3-25 D0-75 38 45 3-50 1-50 2-00 Dl-00 After 45 years of age the records of the table suggest the presence of other influences in the eye, which determine an increase of the Hm. as well as the diminution of the ciliary power. CONCLUSIONS. 1. That through this instrument from 50*00 to 100-00 per cent, of manifest hyperopia can be detected.