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Journal of Biomedical Optics

Asphericity analysis using corneal wavefront and topographic meridional fits
Author(s): Samuel Arba-Mosquera; Jesus Merayo-Lloves; Diego de Ortueta
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Paper Abstract

The calculation of corneal asphericity as a 3-D fit renders more accurate results when it is based on the corneal wavefront aberrations rather than on the corneal topography of the principal meridians. A more accurate prediction could be obtained for hyperopic treatments compared to myopic treatments. We evaluate a method to calculate corneal asphericity and asphericity changes after refractive surgery. Sixty eyes of 15 consecutive myopic patients and 15 consecutive hyperopic patients (n=30 each) are retrospectively evaluated. Preoperative and 3-month-postoperative topographic and corneal wavefront analyses are performed using corneal topography. Ablations are performed using a laser with an aberration-free profile. Topographic changes in asphericity and corneal aberrations are evaluated for a 6-mm corneal diameter. The induction of corneal spherical aberrations and asphericity changes correlates with the achieved defocus correction. Preoperatively as well as postoperatively, asphericity calculated from the topography meridians correlates with asphericity calculated from the corneal wavefront in myopic and hyperopic treatments. A stronger correlation between postoperative asphericity and the ideally expected/predicted asphericity is obtained based on aberration-free assumptions calculated from corneal wavefront values rather than from the meridians. In hyperopic treatments, a better correlation can be obtained compared to the correlation in myopic treatments. Corneal asphericity calculated from corneal wavefront aberrations represents a 3-D fit of the corneal surface; asphericity calculated from the main topographic meridians represents a 2-D fit of the principal corneal meridians. Postoperative corneal asphericity can be calculated from corneal wavefront aberrations with higher fidelity than from corneal topography of the principal meridians. Hyperopic treatments show a greater accuracy than myopic treatments.

Paper Details

Date Published: 1 March 2010
PDF: 9 pages
J. Biomed. Opt. 15(2) 028003 doi: 10.1117/1.3382910
Published in: Journal of Biomedical Optics Volume 15, Issue 2
Show Author Affiliations
Samuel Arba-Mosquera, SCHWIND eye-tech-solutions GmbH & Co. KG (Germany)
Jesus Merayo-Lloves, Univ. de Valladolid (Spain)
Diego de Ortueta, SCHWIND eye-tech-solutions GmbH & Co. KG (Germany)

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