Structural similarities between human and octopus eyes. Even though there are some differences between human and octopus eyes, each of the tissues such as eyelid, cornea, pupil, iris, ciliary muscle, lens, retina, and optic nerve/ganglion corresponds well to each other. The octopus eye forms from an epidermal placode through a series of successive infoldings, whereas the human eye forms from the neural plate and induces the overlying epidermis to form the lens (Harris 1997). The differences in developmental processes between human and octopus are explained in the same reference (Harris 1997). This figure was modified with permission from Sinauer Associates, Inc., © 1990 (Brusca and Brusca 1990).
