Ocular scattering is an optical phenomenon that degrades the retinal image in the human eye, similar to the effects of ocular aberrations or diffraction. However, there is still a lack of standardization in defining and measuring ocular scattering. Several devices and procedures have been described during the last decade, but most have not been validated or been shown to be reliable. The development of a standard procedure for measuring and describing ocular scattering is an ongoing subject in visual science. This review aims to provide a general definition of the concept of ocular scattering, based on the work of previous authors, and to highlight the advantages and disadvantages of measurement techniques that have been described.