The entire retina is part of the CNS, aka “the brain”. The optic nerve is therefore part of the brain. There are dopaminergic amacrine cells within the retina

The entire retina is part of the CNS, aka “the brain”. The optic nerve is therefore part of the brain. There are dopaminergic amacrine cells within the retina and dopamine receptor much more widely. Here is a reference with some of original citations: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2865197/#R36 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2865197/#R36