Transparency of the lens and the eye

Summary Eye media transparency, and in particular that of the crystalline lens, is a requirement for good vision. Incipient lens opacification reduces retinal illumination and also increases intraocular scattering, producing unwanted visual artifacts, such as glare, that affect retinal image quality. A ripe cataract results in blindness. Even before a cataract can be observed and diagnosed, intraocular scattering is known to gradually increase with age but also to depend on genetic and environmental factors. Precise quantification of intraocular scattering can be a very useful tool to study some aspects of the eye's aging process and to develop an objective classification method for cataracts. However, this is not a simple task, especially at an early stage. In recent years, several objective, subjective or mixed‐approach procedures and devices have been developed, aiming to tackle this issue. In this talk, the effects of a decreased lens transparency and increased will be summarized, the factors involved in the progression of this condition will be reviewed, and the methods to quantitatively study the problem will be briefly discussed.