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KK Liedel, JA Campin, GH Pettit, GP Gray; Effect of Cycloplegic Agents on Wavefront Aberrations . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2052.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Wavefront measurements are often made after drug-dilation of the pupil to maximize the measurement zone size. Concerns have been raised as to whether pharmacologic cycloplegia alters the aberration content in the wavefront. Because the center of the pupil may shift with dilation, aberration changes may be detected if the pupil center is used as the origin for the wavefront description. The following study was performed to assess whether true aberration changes occur in the eye with drug dilation, using a consistent reference axis for the wavefront reconstruction. Methods: The LADARWaveTM CUSTOMCORNEA® Wavefront System, a Hartmann-Shack type device, was used to measure visual aberrations for 10 volunteer patients (20 eyes). This device includes hardware and software features that allow accurate measurement of the natural pupil center with respect to the limbus, and subsequent wavefront reconstruction in relation to this point. In addition the fixation subsystem automatically "fogs" the fixation target to minimize patient accommodation. For each eye the daytime pupil center/limbus geometry was first measured, then naturally dilated ("dark adapted") wavefront measurements were made. The eyes were then dilated with 1% Tropicamide, and after 30 minutes repeat wavefront measurements were taken. Five measurements were made during each session. The data was then analyzed to compare intra- versus inter-session variations. Results: Preliminary analysis revealed an average hyperopic shift of approximately 0.25 D in the defocus term when going from the naturally to drug-dilated pupil state. No consistent trends were observed for other wavefront aberrations up to fourth order when a consistent origin (daytime pupil center) was used in the mathematical descriptions. In contrast, significant differences were seen if each wavefront reconstruction was based on the dilated pupil center instead of the consistent reference. Conclusion: Drug dilation of the eye appears to have a small impact on the defocus error but not on other aberrations. However, significant differences may be perceived if a consistent reference axis is not used for the mathematical wavefront description.
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