Age-related lens changes include: a) the progressive increase in lens mass with age, b) changes in the point of insertion of the lens zonules, and c) a shortening of the radius of curvature of the anterior surface of the lens. With age, there is also decreased light transmission by the lens associated with increased light scatter, increased spectral absorption—particularly at the blue end of the spectrum—and increased lens fluorescence. Besides these physiological modifications, we must take into consideration the additional effects caused by exposure to external physical and chemical agents such as ultraviolet rays and drugs, which lead to considerable densitometric changes and consequently to modifications in optical lens quality. At present, new instruments allow the analysis, in clinical practice, of qualitative and quantitative alterations of the lens that occur with aging, confirming objectively the degradation of the optical quality of the crystalline lens.