Purpose: To study how test results of wavefront aberrations are affected by displacement during wavefront measurement.
Methods: A Shack-Hartmann based wavefront sensor was used to measure an artificial eye at controlled positions along axial and lateral directions. We use deviation amplitude and relative deviation amplitude to study the changes of reconstructed wavefront aberrations during the displacement within 1.00 mm. The analysis was performed with a 4th-order Zernike polynomial expansion with the 0th-order (piston) and 1st-order (tip and tilt) removed. RMS of the whole and each order are studied.
Results: Effects caused by movement along axis within 1.00 mm are not apparent. A dramatic change was observed in relative deviation amplitude during the movement off the center, although the absolute value of changes are small. The changes are highly polynomials depended. RMS stays relatively stable during both procedures.
Conclusions: When wavefront aberration is introduced into customized refractive surgery, it is important for physicians to align the device during measurements, particularly in lateral direction.