高频采样下人眼波像差特性研究

Abstract

Temporal properties of ocular wave aberrations are researched to improve the performance of eye aberration correction based on adaptive optical systems and the result for retinal imaging. Using a Shack-Hartmann wavefront sensor at a sampling rate of 330 Hz and exposure time of 3 ms, an optical system is constructed to detect human eye's wave aberration. The averaged root mean square (RMS) of detecting errors of the system is proved to be 0.01 by error analysis and an experiment on schematic eye. Detection results show that the existence of fluctuations of ocular wave aberration above 150 Hz can probably impact the performance of adaptive optics systems for wave aberration correction. These fluctuations can be reduced by increasing the detection and exposure times of the detector. In order to reach the diffraction limit, for eyes in the state of steady gaze, correction residual error RMS of adaptive optical system is less than /14, when detecting exposure time is 3 ms and detecting correction period is less than 45 ms. while the detecting correction period can increase to 62 ms as long as the exposure time is set to 6 ms. Analysis on tilt aberration proves that exposure time of high resolution retinal imaging should be less than 9 ms to avoid horizontal movements. Weighting the tradeoff between aberration fluctuation and horizontal movements, exposure times of detection and imaging are both set to about 6 ms.