Abstract: Melanin in ocular fundus is mainly located in retinal pigment epithelia and choroidal melanocytes. Beingmainly derived from melanin, near-infrared fundus auto-fluorescence can be used to evaluate the functions of retinal pigment epithelia and choroidal melanocytes, because depigmentation is often an early sign of dysfunction in these cells. This article systematically reviews the types of melanin, the formation of melanosomes, the chemical composition and synthesis of melanin, its toxicological properties, photoprotective effects, changes with age, spectral characteristics and associated clinical applications. The purpose is to improve the understanding of near-infrared fundus autofluorescence imaging, which is of great benefit in the current era when genetic diagnosis and treatment of retinal pigment epithelium-related diseases are about to be widely carried out.

Key words:  Melanin, Near-infrared fundus autofluorescence, Retina