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O. K. Klaproth, J. Buehren, T. Kohnen; Ocular Static and Dynamic Cyclorotations in Laser Refractive Surgery. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2535.
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© ARVO (1962-2015); The Authors (2016-present)
To describe the amount, directions and frequency spectra of pre- and intraoperative cyclorotational eye movements in laser refractive surgery.
Retrospective analysis of static preoperative cyclorotations (static cyclorotation) and dynamic intraoperative cyclorotations (dynamic cyclorotation) of 409 and 279 eyes, respectively that underwent myopic LASIK from March 2007 to February 2009 with ACE 100 eye tracker (Technolas Perfect Vision, Munich, Germany). Values were analyzed for absolute size, range and direction of static rotation. Theoretical cylindrical undercorrection was calculated. Dynamic rotational eye movements were analyzed using temporal power spectra obtained by Fourier analysis. The f95 criterion was defined as the frequency below which 95% of eye movements occur. Multiple regression analysis was used to assess potential influence of demographic data, order of treatment and refractive data on f95. The overall significance level was set to p=0.05.
Mean absolute static cyclorotation was 3.01°±2.41° ranging from 0° to 12.3°, resulting in a theoretical cylindrical undercorrection of 0.25D in 10.5%, 0.5D in 3.5%, 0.75D in 1.2% and 1.0D in 0.5% of eyes. Eyes treated first in a bilateral session rotated significantly less than the eyes treated secondly (2.76°±2.38° vs. 3.28°±2.41°; p <0.01). Mean maximum absolute intraoperative deviation from preoperative zero was 3.11°±2.81° (0°-14.75°). Mean absolute range of dynamic cyclorotation was 6.62°±3.33° (0°-16.25°). Temporal power spectra showed a dominance of high-frequency, low-power cyclorotations, however, low-frequency, high-power cyclorotations occured as well. Mean f95 threshold of rotational movements was 4.93±2.15 Hz (0.44 to 9.23 Hz). Multiple regression analysis did not reveal any relationship between order of treatment, demographic or preoperative refractive data and f95 of dynamic cyclorotation.
Ocular cyclorotation might reach orders of magnitude that are relevant for the precision of laser refractive surgery. Dynamic rotational ocular movements are dominated by high-frequency, low-power cyclorotations.
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