Final answer:
The 'white' of the eye is known as the sclera, which is a part of the fibrous tunic, the eye's outermost tissue layer responsible for maintaining the shape of the eyeball.
Step-by-step explanation:
The "white" of the eye is called the sclera, and it forms the posterior portion of the fibrous tunic. This outer layer of the eye is primarily made up of connective tissue and is responsible for maintaining the shape of the eyeball. The sclera accounts for five-sixths of the surface of the eye, though most of it is not visible due to its location. In contrast, the clear cornea covers the anterior tip of the eye and is part of the fibrous tunic as well, allowing light to enter the eye.
In the structure of the eye, the fibrous tunic is the outermost layer, followed inner by the vascular tunic, which includes the choroid, ciliary body, and iris, and lastly by the neural tunic, or retina. Each of these tunics has specific functions crucial for vision. For instance, the vascular tunic provides blood supply through the choroid, and the ciliary body and iris assist in focusing and regulating the amount of light that enters the eye through the pupil. The neural tunic, specifically the retina, is essential for photoreception.