ABSTRACT
In physical optics, light is considered as a wave, and the light wave spreads in all directions as a spherical wave. The wavefront is the shape of light waves that are all in phase (1). The ideal eye, defined as an emmetropic eye without any aberrations, has a perfect wavefront, described as a plane perpendicular to the line of sight (Fig. 1) (2). For real eyes, wavefronts that converge toward the retina are not spherical, so perfect imaging never occurs.
