The eye itself can be divided into 3 concentric tunics plus the internal components. The three tunics from the outside surface of the eye inward are, (1) the fibrous tunic (cornea and sclera), (2) the vascular tunic (iris, ciliary body, and choroid) and (3) the neuroectodermal (nervous) tunic (retina). These tunics inwardly decrease in size as they become more specialized. Internally, the eye contains the lens and the aqueous and vitreous humors.
Below is a breakdown of the eye structure:
3 Concentric Tunics
1. Fibrous Tunic
2. Vascular Tunic
3. Nervous Tunic