Calibration of a Shack-Hartmann Sensor (SHS) with a point diffraction interferometer (PDI) to measure the wavefront aberrations of the human eye

To measure the wavefront aberrations of human eyes, a Shack-Hartmann Sensor (SHS) was developed at UNAM-CCADET. Usually, for calibrating the SHS a well corrected collimated beam is used, so the evaluation of the aberrations depends on this calibration. We propose to use a Point Diffraction Interferometer (PDI) in parallel with the SHS, in order to be able to check for aberrations in the calibration beam at any time. This allows reducing the delay between the calibration and measurement of the aberrations of the eye made with the SHS. In addition, both measurements are made without moving components, so the evaluation made through the SHS can be compensated with the reference beam measurement made by the PDI. The results of the quantitative evaluation of the wavefront aberrations of a human eye are presented in this paper.