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RM Hazarbassanov, A Grimbaum, I Kaiserman; Comparison of Pre- and Post-LASIK High Order Wavefront Aberrations Measured at Various Optic Zones . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2063.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To quantify the effect of the abberometer's optic zone on the evaluation of the high order aberrations pre- and post-LASIK using. Methods: 102 eyes of 51 myopic-astigmatic patients (-1.5D to -13.25D) that underwent LASIK (WaveLight-Allegretto scanning-spot laser) were examined using the WaveLight WaveFront analyzer (a Tscherning aberrometer) pre-operatively and 1 day, 1week, 1 month and 3 months post-op. The aberrometry was performed at various optic zones (OZ) ranging from 4 to 6.5 mm (under mydriasis). In addition subjective and objective refraction, corneal topography (Oculus) and pupilometry were performed. We looked at the Zernike decomposition of the wave aberration up to the 6th order and compared the root mean square (RMS) of the wavefront error for the high order aberrations (3-6th order) including coma and spherical aberrations. Results: Post-LASIK the high order aberrations in general and coma and spherical aberrations specifically increased significantly (from a mean RMS of 0.22µm to 0.49µm). The difference in the RMS of high order aberrations was significantly larger when measured through a 6.5mm OZ compared to a 4mm OZ. The low order aberrations such as defocus and astigmatism were much less affected by the size of the aberrometer's OZ. Conclusion: While correcting defocus and astigmatism, LASIK induces a significant increase in high order aberrations especially at optic zones beyond 5mm. Changing the aberrometer's optic zone can help us evaluate these effects.
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