AOPEP and myopia: Studies have shown that increasing DA content by injecting DA directly into the eye or using levodopa to promote DA synthesis, or enhancing DA signaling by nonselective DA receptor agonists such as APO and 2-amino-6, 7-dihydroxy-1, 2, 3, 4-tetrahydronaphthalene hydrobromide can prevent the development of myopia.[11] Therefore, reduced DA content is an important cause of myopia, which may specifically include reduced DA synthesis, reduced release, and increased destruction, or DA receptors affected resulting in reduced DA content.