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August 27, 1892

WHAT MAY BE CONSIDERED NORMAL CORNEAL ASTIGMATISM? FROM KERATOMETRIC MEASUREMENTS OF THREE HUNDRED EYES.Read in the Section of Ophthalmology at the Forty-third annual meeting of the American Medical Association, held at Detroit, Mich., June, 1892.

Author Affiliations


JAMA. 1892;XIX(9):243-248. doi:10.1001/jama.1892.02420090005002c

Keratometry is now considered an essential to the examination of the ocular refraction. As the principal seat of astigmatism is in the cornea there can be no doubt but that the measurement of its curvature is both time and labor saving; and in the near future this fact will be appreciated by every reputable ophthalmist. Correction of refractive errors is the most scientific portion of an oculist's work and cannot be done properly without several means of objective examination.

The ophthalmometer of Javal and Schöitz is conceded to be the most practical instrument for the estimation of the corneal curvature. In the accompanying instructions, in treatises and text books, the corneal is taken as equal to the whole astigmatic error. In 1882 Javal reported that in the measurement of 100 eyes in 96 per cent, the corneal corresponded exactly with the total astigmatism. His associate Nordensen followed later with a