1Mrochen M. C., 2Jankov M., 3Seiler T.

3Augenklinik, UniversitätsSpital Zürich, Schweiz; 2Departamento de Oftalmologia, Santa Casa de Sao Paulo, Brasil; 1ETH, Zürich, Schweiz

Objective: The Zernike expansion of measured wavefront aberration also includes spherical and cylindrical data of the subject's eye. The aim of this study was to compare the wavefront and manifest refraction in eyes with small and large higher order optical aberrations.
Methods: Wavefront aberrations were measured in 70 untreated and 16 treated eyes by means of an Tscherning-type aberrometer after having dilated the pupils to a diameter of at least 6.5 mm. The wavelength used in the measuring device was 532 nm. The manifest refraction was determined prior to the wavefront sensing procedure.
Results: In the group of untreated eyes, 96% of the investigated eyes were within ±1.0 D of the manifest refraction. In contrast, the eyes with large higher order aberrations exhibit significant differences as high as 2 D between wavefront and manifest refraction.
Conclusion: Higher order optical aberrations can lead to clinically relevant differences in wavefront and manifest refraction of several diopters. The observed differences are due to differences in the pupil diameter during wavefront sensing and manifest refraction measurements and are also a result of a misinterpretation of the higher order optical aberrations with sphero-cylindrical glasses. Such a misinterpretation might lead to a higher unpredictability of the refractive surgery results should they be based only on the manifest refraction data.

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