Human eye layer, known as the fibrous tunic, is composed of the cornea and sclera. The middle layer, known as the vascular tunic or uvea, consists of the choroid, ciliary body, pigmented epithelium and iris. The innermost is the retina, which gets its oxygenation from the blood vessels of the choroid (posteriorly) as well as the retinal vessels (anteriorly). The spaces of the eye are filled with the aqueous humour anteriorly, between the cornea and lens, and the vitreous body, a jelly-like substance, behind the lens, filling the entire posterior cavity. The aqueous humour is a clear watery fluid that is contained
Ocelloid hypothesized to represent the eye of a multicellular organism coincidentally engulfed by a single-celled organism. The possibility that it had an evolutionary relationship to plastids had been considered at least since the 1970s, although until the 2010s direct evidence was scarce. Ocelloids contain subcomponents analogous to eye structures including the lens, cornea, iris, and retina. It can be divided into two substructures, the translucent, roundish "hyalosome" and the heavily pigmented "melanosome", also known as the retinal body or pigment cup. The hyalosome serves as the refractive lens of the ocelloid; it is surrounded by a layer of mitochondria serving as