https://www.cnet.com/news/scientists-grow-human-eye-parts-to-determine-how-we-see-in-color/ > The eye organoid used in the John Hopkins study produces a miniature retina, the layer of cells at the back of the eyeball that process light, creating the electrical impulses the brain can use to produce vision. Within the space are cone-shaped cells, known as cones, which are able to detect red, blue and green light. > First, the team confirmed that their retina-organoids-in-a-dish were functioning similarly to real human retinas. Then they watched and studied as the organoids developed.