ANSI Z80.28:2017 pdf download.Ophthalmics一Methods of Reporting Optical Aberrations of Eyes.
ANSI Z80.28 specifies standardized methods for reporting the optical aberrations of eyes.
2. Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication. the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.
ISO 8429: 1986, Optics and Optical Inst ruinents — Ophthalmology — Graduated Dial Scale
3. Symbols and Definitions
Symbols used in this standard are summarized in Table 1.
3.1 Line of sight The line of sight is the line from the point of interest in object space to the center of the entrance pupil of the eye and continuing from the center of the exit pupil to the retinal point of fixation (generally the foveola).
3.2 Zernike polynomial function A Zernike polynomial function is one of a complete set of functions defined and orthogonal over the unit circle; parameterized by a dimensionless radial parameter, p. and a dimensionless meridional parameter 0; designated by a non-negative radial integer index ii and a signed meridional index in. Each Zernike polynomial function is the product of three terms — a normalization term, a radial term and a meridional term — so that a Zernike polynomial function with indices 11 and in is given by the equation:
Each set of Zernike coefficients has associated with it the aperture diameter that was used to generate the set from surface elevation data. The set is incomplete without this aperture information.
(See annex A for information on a method to find Zernike coefficients from wavefront slope (gradient) data)
3.3.1 Normalized Zernike coefficient A normalized Zernike coefficient is generated using normalized Zernike functions and is designed to be used with them to reconstruct a surface. Normalized Zernike coefficients have dimensional units of length.
3.3.2 Un-normalized Zernike coefficient An un-normalized Zernike coefficient is generated using un-normalized Zernike functions and is designed to be used with them to reconstruct a surface. Un-normalized Zemike coefficients have dimensional units of length.ANSI Z80.28 pdf download.