Purchase this article with an account.
T. D. Raymond, D. Neal, S. Farrer, C. D. Baer; The Correlation of Combined Topo/Wavefront Measurements. Invest. Ophthalmol. Vis. Sci. 2010;51(13):5652.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
A high-resolution aberrometer and a Full-Gradient Corneal Topographer (FGCT) have been combined to yield spatially-registered, temporally-proximate, and co-aligned wavefront (WF) and FGCT data. We investigate the correlation between WF, FGCT, and internal ocular aberrations.
Multiple high-resolution WF and CT measurements of 49 eyes (mean age 45 ranging from 30-70) have been analyzed in a retrospective study. The WF and CT measurements are described by Zernike polynomials determined by fitting the slope data over the pupil area; the pupil was determined by analysis of the WF sensor spots. The internal ocular contribution to the overall wavefront aberration is determined by term-by-term subtraction of the FGCT wavefront aberration from the WF aberration internal ocular aberrations. The second through fourth order coefficients for these co-aligned wavefront surfaces are correlated using linear correlation and multivariate analysis methods.
Multivariate correlation coefficients between internal ocular and corneal aberrations were found for the z3, z5, z6, z7, z8, z9, z10, z11, z12, z13, and z14 terms to be -.57, -0.34, +0.0039, -0.88, -0.93, -0.055, -0.35, -0.73, -0.93, -0.63, and -0.40, respectively. Unlike previous similar studies, a strong correlation was observed for vertical coma. The correlations were low for the trefoil terms.
The multivariate correlation between internal and corneal aberrations is found to be high for many of the third and fourth order radial order terms. The FGCT may correlate better to the total wavefront measurement than in studies using Placido corneal topographers because of the FGCT’s ability to determine the full gradient of the cornea and because the measurement locations are more uniformly distributed. The co-axial and spatially and temporally-registered nature of the WF and FGCT may also improve the correlation.
This PDF is available to Subscribers Only