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Wavefront measurement proves most accurate 3 to 5 seconds after blinking
J Refract Surg. 2009;25(1):59-68.
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Decreased dispersion of wavefront aberrations at a precise interval after blinking was found to ensure the most accurate measurement of aberrations.
The study included 42 volunteers who underwent wavefront analysis. Investigators took 150 images, or about six frames per second, during an interval between blinks. Primary outcome measures were spherical and cylindrical refraction, root-mean-square values for spherical, coma and higher-order aberrations, fluctuation of trends, prevalence of trends, tear production status and tear film breakup time.
Data showed that early minimum type 1 fluctuations were significantly more frequent than trends with a type 2 early local maximum for total higher-order aberrations (P = .036). The rate of type 1 fluctuation trends was significantly higher for coma and total higher-order aberrations in subjects with normal tear film breakup time than in subjects with abnormal results, the study authors said.
"We suggest that wavefront aberrations can be measured most accurately at the time after blink when they exhibit a decreased degree of dispersion," they said. "We recommend that a snapshot of wavefront measurements be made 3 to 5 seconds after blink."