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THE FREQUENCY OF ASTIGMATISM

THE FREQUENCY OF ASTIGMATISM Abstract Since the introduction of the ophthalmometer into clinical ophthalmology, many authors have studied the variations of the curvature of the cornea. Steiger, who was the first to apply statistical methods to this study, found that the variations of the corneal curvature behaved very regularly and followed the law of Gauss. The next logical step was to investigate the distribution of the various degrees of corneal astigmatism over the three main refractive states, emmetropia, myopia and hyperopia. This classification, mainly on Steiger's suggestion that all the refractive states should be considered as physiologic variations of normal refraction, was learned to be an arbitrary procedure which was not justified by any biologic facts. Therefore, the frequency of the various degrees of corneal astigmatism was determined separately for each refractive state. Extensive studies of this type, using skiascopy without cycloplegia and manifests for the determination of axial refraction and then correlating References 1. Menestrina, G.: Astigmatismo corneale ed ametropie assili , Arch. di ottal. 33:399, 1926. 2. Donders, F. C., quoted by Hess (footnote 9). 3. Tron, E.: Variationsstatistiche Untersuchungen über Refraction , Arch. f. Ophth. 122:1, 1929. 4. Nicoletti, G.: The Influence of the Posterior Surface of the Cornea on the Total Astigmatism , Ann. di ottal. e clin. occul. 55:987, 1927. 5. It should be kept in mind that by "astigmatic meridian" is meant, that the meridian concerned was found in an eye combined with another meridian of different strength (minimum difference 0.5 diopter). 6. Pomeroy, O.: Progressive Hyperopic Astigmatism , Tr. Am. Ophth. Soc. , 1867, p. 30. 7. Theobald, S.: Progressive Astigmatism , Tr. Am. Ophth. Soc. , 1885, p. 29. 8. Jackson, E.: Progressive Hyperopic Astigmatism , Tr. Am. Ophth. Soc. , 1890, p. 676. 9. Hess, C.: The Anomalies of Refraction and Accommodation of the Eye in Graefe-Saemisch: Handbuch der Gesamten Augenheilkunde , ed. 2, Leipzig, Wilhelm Engelmann, 1901-1911, vol. 8, part 2, p. 420. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Ophthalmology American Medical Association

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Publisher
American Medical Association
Copyright
Copyright © 1930 American Medical Association. All Rights Reserved.
ISSN
0003-9950
eISSN
1538-3687
DOI
10.1001/archopht.1930.00810140085006
Publisher site
See Article on Publisher Site

Abstract

Abstract Since the introduction of the ophthalmometer into clinical ophthalmology, many authors have studied the variations of the curvature of the cornea. Steiger, who was the first to apply statistical methods to this study, found that the variations of the corneal curvature behaved very regularly and followed the law of Gauss. The next logical step was to investigate the distribution of the various degrees of corneal astigmatism over the three main refractive states, emmetropia, myopia and hyperopia. This classification, mainly on Steiger's suggestion that all the refractive states should be considered as physiologic variations of normal refraction, was learned to be an arbitrary procedure which was not justified by any biologic facts. Therefore, the frequency of the various degrees of corneal astigmatism was determined separately for each refractive state. Extensive studies of this type, using skiascopy without cycloplegia and manifests for the determination of axial refraction and then correlating References 1. Menestrina, G.: Astigmatismo corneale ed ametropie assili , Arch. di ottal. 33:399, 1926. 2. Donders, F. C., quoted by Hess (footnote 9). 3. Tron, E.: Variationsstatistiche Untersuchungen über Refraction , Arch. f. Ophth. 122:1, 1929. 4. Nicoletti, G.: The Influence of the Posterior Surface of the Cornea on the Total Astigmatism , Ann. di ottal. e clin. occul. 55:987, 1927. 5. It should be kept in mind that by "astigmatic meridian" is meant, that the meridian concerned was found in an eye combined with another meridian of different strength (minimum difference 0.5 diopter). 6. Pomeroy, O.: Progressive Hyperopic Astigmatism , Tr. Am. Ophth. Soc. , 1867, p. 30. 7. Theobald, S.: Progressive Astigmatism , Tr. Am. Ophth. Soc. , 1885, p. 29. 8. Jackson, E.: Progressive Hyperopic Astigmatism , Tr. Am. Ophth. Soc. , 1890, p. 676. 9. Hess, C.: The Anomalies of Refraction and Accommodation of the Eye in Graefe-Saemisch: Handbuch der Gesamten Augenheilkunde , ed. 2, Leipzig, Wilhelm Engelmann, 1901-1911, vol. 8, part 2, p. 420.

Journal

Archives of OphthalmologyAmerican Medical Association

Published: Dec 1, 1930

References