Is this what you're referring to?: > In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths of the developing brain, speci

Is this what you're referring to?: > In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths of the developing brain, specifically the embryonic diencephalon; thus, the retina is considered part of the central nervous system (CNS) and is actually brain tissue.[2][3] From https://www.britannica.com/science/retina https://www.britannica.com/science/retina > Retina, layer of nervous tissue that covers the inside of the back two-thirds of the eyeball, Anyway. I'm still not convinced eyes = retina = brain so ill leave it there.