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J Straub, J Schwiegerling, A Gupta, J Miller, R Anwaruddin; Spherical Aberrations in Human Eyes: Comparison of normal, post-LASIK, and post-IOL eyes . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2037.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the accuracy and repeatability of measurements of aberrations in human eyes with a Shack-Hartmann Aberrometer that has been built and is used at the University of Arizona. Measurement and characterization of spherical aberrations in normal subjects (n=17), dilated normal subjects (n=7), post-LASIK subjects (n=7), and pseudophakic subjects (IOL, n=2). Methods: We tested the accuracy of the Aberrometer with an optical model eye using ophthalmic lenses and test lenses with known spherical aberrations. We tested the accuracy with human eyes by testing one subject’s eye with ophthalmic lenses placed in front. In another test we measured the prescription of 22 eyes with the Aberrometer and an Autorefractor (Zeiss Humphrey). We tested repeatability by taking repeated measures of 66 eyes. For patients with dilated pupils larger than 6mm, the Zernike aberration coefficients were calculated for a 6mm pupil. Results: Measurement error when measuring ophthalmic lenses with an optical model eye: sphere 0.150.31D (range 10D, n=24), sphere 0.561.03D (range 20D, n=37), cylinder 0.200.30D (range 8D), and axis 1º (n=14). Spherical aberrations were measured with an error of 0.0250.010 microns (n=18). Measurement error when measuring ophthalmic lenses with a human eye: -0.050.47D (range 7D, n=20). Autorefractor and Aberrometer measurements showed a difference of -0.400.86D for sphere (range 0 to -9.5D), and 0.560.31D for cylinder (range 0 to +3.5D, n=22). Repeatability of the measurements: 0.0520.119 microns for each Zernike coefficient (n=5424). Spherical aberrations in human eyes were found as follows: normal subjects (0.060.14 microns), dilated normal subjects (0.090.10 microns), post-LASIK (0.450.12 microns), and IOL (0.580.25 microns). Conclusion: The tests with the optical model eye validated the measurements with the Shack-Hartmann Aberrometer for spherical and cylindrical refractive error as well as for spherical aberrations. At a 6mm pupil, IOL and post-LASIK subjects have significantly higher spherical aberrations than normal subjects (p<0.05). No differences were found between the dilated normal and the normal group (p≷0.05).
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