Videokeratoscopic data are generally displayed as a color-coded map of corneal refractive power, corneal curvature, or surface height. Although the merits of the refractive power and curvature methods have been extensively debated, the display of corneal surface height demands further investigation. A significant drawback to viewing corneal surface height is that the spherical and cylindrical components of the cornea obscure small variations in the surface. To overcome this drawback, a methodology for decomposing corneal height data into a unique set of Zernike polynomials is presented. Repeatedly removing the low-order Zernike terms reveals the hidden height variations. Examples of the decomposition-and-display technique are shown for cases of astigmatism, keratoconus, and radial keratotomy.
© 1995 Optical Society of America
Original Manuscript: November 23, 1994
Revised Manuscript: April 17, 1995
Manuscript Accepted: May 15, 1995
Published: October 1, 1995
Jim Schwiegerling, John E. Greivenkamp, and Joseph M. Miller, "Representation of videokeratoscopic height data with Zernike polynomials," J. Opt. Soc. Am. A 12, 2105-2113 (1995)