Melasma is a hyperpigmentation disorder that is probably exacerbated by visible light. Opsin
receptors (OPN 1, 2, 3, 4 y 5) were described in the skin, being capable of activating
melanogenesis induced by visible light. The aim of this study was to evaluate the expression
of OPN in melasma skin and its changes following treatment with UV-Vis filter and 0.05%
retinoic acid for 12 weeks.