The Role of Chromatic Aberration in Vision

The study of biological optics would be complicated enough if light only came in a single wavelength. However, altering the wavelength (or distribution of wavelengths) of light has multiple effects on optics, including on diffraction, scattering (of various sorts), transmission through and reflection by various media, fluorescence, and waveguiding properties, among others. In this review, we consider just one wavelength-dependent optical effect: longitudinal chromatic aberration (LCA). All vertebrate eyes that have been tested have significant LCA, with shorter (bluer) wavelengths of light focusing closer to the front of the eye than longer (redder) wavelengths. We consider the role of LCA in the visual system in terms of both how it could degrade visual acuity and how biological systems make use of it.