You can compare the eye to a camera that sets the picture formation. The front part of the eye consists of the cornea and the eye lens that accumulates the light and focus attention on what you are looking at. The aperture opening (the pupil) determines how much light you get into your eye. The coloured part of the eye (the iris) surrounds the pupil.
The camera house (the vitreous) is the transparent inner part that fills the eye. In the back of the eye there is a film (the retina). Here is the sans cells of the eye where the picture is formed. The retina cells (the nerve fibres) gathers in the sight nerve. The tear fluid forms in the eye gland, cleans the eye, and adds lubricant. The white part of the eye (sclera) consists of connective tissue. There is a transparent mucosa on the outside where the tear fluid distributes evenly. The tear fluid forms in the eye gland and lubricates the eye. A well-functioning tear fluid is important in order to have a proper and untroubled sight. The tear fluid keeps the eye surface smooth so the sight is clear and removes foreign objects from the surface of the eye. The tear fluid consists of liquid, lubrication grease, different salts and nourishing and bactericidal matters. It has a slightly gluing texture that keeps the tear fluid on to the eye, so it does not run down to fast. The fatty lair is most far from the eye and prevents the fluid to evaporate too fast.