Visual interaction of 2nd to 5th order Zernike aberration terms with vertical coma.

While most interactions reduced visual image quality, combinations of C(3, -3) (vertical trefoil) and C(5, -1) (vertical secondary coma) provided a clinically relevant beneficial effect in the presence of C(3, -1) (vertical coma) which was demonstrated in both through-focus simulation and chart reading tests. Future work will examine whether these effects persist in the presence of the entire spectrum of residual aberrations seen in the eyes of individuals with keratoconus.