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CHANGES IN THE ORIENTATION OF THE AXIS OF ASTIGMATISM ASSOCIATED WITH AGE
Author(s) -
Saunders H.
Publication year - 1986
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1111/j.1475-1313.1986.tb00727.x
Subject(s) - astigmatism , orientation (vector space) , oblique case , regression , optometry , basis (linear algebra) , optics , mathematics , physics , geometry , medicine , statistics , linguistics , philosophy
— A new regression equation for the change in the axis of astigmatism with age, as deduced from cross‐sectional studies, is presented. Possible artefacts arising from the methods used to obtain mean prescriptions are discussed; it is shown that these may result in over‐estimation of the occurrence of oblique cylinders in middle‐age and that a previously demonstrated gradual change of orientation of the axis of astigmatism may have no basis in reality. The need for further longitudinal studies is emphasized.