Power vectors: An application of Fourier analysis to the description and statistical analysis of refractive error
Power vectors: An application of Fourier analysis to the description and statistical analysis of refractive error
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DOI:
10.1097/00006324-199706000-00019
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发表时间:
1997-06-01
影响因子:
1.4
通讯作者:
Horner, D
中科院分区:
文献类型:
--
作者:
Thibos, LN;Wheeler, W;Horner, D
The description of sphere-cylinder lenses is approached from the viewpoint of Fourier analysis of the power profile. It is shown that the familiar sine-squared law leads naturally to a Fourier series representation with exactly three Fourier coefficients, representing the natural parameters of a thin lens. The constant term corresponds to the mean spherical equivalent (MSE) power, whereas the amplitude and phase of the harmonic correspond to the power and axis of a Jackson cross-cylinder (JCC) lens, respectively. Expressing the Fourier series in rectangular form leads to the representation of an arbitrary sphere-cylinder lens as the sum of a spherical lens and two cross-cylinders, one at axis 0 degrees and the other at axis 45 degrees. The power of these three component lenses may be interpreted as (x,y,z) coordinates of a vector representation of the power profile. Advantages of this power vector representation of a sphero-cylinder lens for numerical and graphical analysis of optometric data are described for problems involving lens combinations, comparison of different lenses, and the statistical distribution of refractive errors.