 A decreased molecular weight or a decrease in the degree of polymerization of ocular melanin has been proposed to turn the normally anti-oxidant polymer into a pro-oxidant.In its pro-oxidant state, melanin has been suggested to be involved in the causation and progression of macular degeneration and melanoma.Rasagiline, an important monotherapy drug in Parkinson's disease, has melanin binding properties, and melanoma tumor reducing properties.