Minimising residual aberration in the presence of cyclotorsion uncertainty in refractive surgery

METHODS: Assuming that cyclotorsion error can be estimated and compensated for with a certain level of uncertainty, we formulate a function to modify the wavefront error in order to minimize the residual aberration magnitudes due to cyclotorsion measurement uncertainty. A modal optimum nomogram factor is computed for minimization of the residual aberration for each Zernike mode. We also calculate the optimized residual aberration using the minimization factor.