FIGURE 2.

To determine the amount of coma expected due to decentration of a lens with spherical aberration an 8 mm wavefront was synthesized from the fourth-order Zernike fit of the centered lens measurement (left panel). A 6 mm mask was then created (second panel), and then this wavefront was systematically decentered behind this mask (third and fourth panels). At each incremental decentration, a fourth-order Zernike fit was performed to the resulting masked wavefront to obtain the expected Z₃⁺¹ value at each corresponding level of decentration.