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J. Einighammer, T. Oltrup, T. Bende, B. Jean; Calculating Wavefront Aberration of Pseudophakic Eyes by Real Ray Tracing. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3131. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To determine the wavefront aberration of pseudophakic eyes by real ray tracing (RRT) using their measured geometry, especially regarding absolute values for corneal and total ocular spherical aberration in conjunction with corneal asphericity.
45 pseudophakic eyes were evaluated. The anteriour corneal surface was measured with a prototype topography system developed at our laboratory; the posterior surface was approximated from the anterior (both spline interpolated). The anterior chamber depth was measured with Biovision Axis ® ultrasound device. The geometry of the lens (Alcon AcrySof SA60AT ®) was used according to the manufacturer’s specification (anteriour and posteriour radius of curvature, thickness, refractive index). Axial length was measured with the Zeiss IOLMaster ®. Refractive indices were assumed according to Gullstrand. Corneal and total wavefront aberration was calculated and approximated by Zernike polynomials according to the OSA standard. Corneal asphericities were calculated from topographies and the results of RRT were rechecked using theoretical surfaces. All calculations were done for 4 and 6mm pupil diameter.
4mm pupil: corneal SA was +0.04 ± 0.05 µm; total SA was +0.06 ± 0.05; mean corneal asphericity was -0.24; 6mm pupil: corneal SA was +0.09 ± 0.12 µm; total SA was +0.17 ± 0.13; mean corneal asphericity was -0.28; corneal SA calculated from a theoretical surface using mean radius and mean asphericity was 0.03 for 4mm and 0.13 for 6mm pupil; the Zernike coefficients obtained for a theoretical surface were consistent with the results of the optical design program OSLO ®.
Absolute values for the wavefront aberration are provided for comparison with computational results of other publications or the results obtained from wavefront sensor measurements with special respect for the spherical aberration. Furthermore this is another step in testing the RRT method developed at our laboratory. The consistent results encourage further developing of the method. Applications of RRT are calculation of customized IOLs (aspheric, toric); IOLs after refractive surgery or the calculation of advanced ablation profiles for refractive surgery.
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