Defocus degradation of retinal images in the Maxwellian view

In the Maxwellian view, the defocused retinal image is derived from two superimposed pupil wavefront components: the diffraction pattern that results when the source transilluminating a target is imaged in the eye's entrance pupil and the wavefront deviation associated with defocus. Since the diffraction pattern based on the target configuration will differ from case to case, there is no general theory of defocus degradation such as the optical transfer function in conventional retinal imagery. Nevertheless, depth of focus is always better in the Maxwellian view because the excitation in the wavefront does not fill the pupil fully and uniformly. The robustness to defocus image degradation is illustrated in several examples.