The eye, as an optical system, consists of many components. Each of the components is unique in its own way. Only 12 parts. All of them help us in our vision of the world.
Components Visible Outside
The first component that we see is the eyeball. Its diameter is usually 2.5 cm. Some people have more, others
x is less.
The apple is covered in three shells. The first is a rigid sclera, which protects it from various injuries. Next is the choroid. She feeds the eye. And finally, the latter is rainbow. It is this shell that gives “color” to the eyes of a person. There is a small hole in it: the pupil.
What is inside, or how do we see?
The eye, as an optical system, works constantly. Even when we sleep, the apple is in motion. Once in a room, this sophisticated device starts continuous operation.
The pupil is first involved. It narrows or expands depending on the degree of illumination of the place. If it is dark, it becomes larger; if it is light, it is smaller.
Further, the information enters the lens of the eye (biconvex lens) and the cornea. Together they form a kind of focusing lens. Yes eye like
The optical system is a very complex and unique device.
The cornea is a more important component than the lens because it plays a large role in focusing and refracting light. She has a stable character - she is motionless. But the eye cannot see simultaneously near and far. This is where the lens comes to the rescue. By instantly changing its curvature, it allows you to see. Such a curvature after aiming at the object is called accommodation.
At the same time, in order to consider what is located nearby, the muscles have to strain very much. Such an overstrain can lead to myopia or farsightedness.
Deeper still
Refracting, the rays fall on the retina, where an inverted image of the object is immediately formed. However, the eye, as an optical system, is unique, and a picture arrives in the brain that is convenient for us.
The retina also contains visual receptors: rods (130 million) and cones (7 million). The former are responsible for vision in the dark, the latter in light. Thus, it is cones after a complex photochemical reaction that supply a color picture to the brain. In total, there are three shades (red, green, blue-violet) that, when mixed, give such a rich image. It is proved that in men, blue cones are very ma
lo, and they practically do not distinguish this color.
Exactly opposite the pupil is a yellow spot or a place in which only the cones are located. This is where the sharpest image is projected. When a person looks at an object, the eye automatically adjusts so that part of the object falls into this zone. Then the picture is transmitted to the brain without distortion.
Information in the center of all human activity enters through the optic nerve. It is he who serves as a conductor, transmitting the picture.
The drainage system of the eye performs a protective function. It is she who causes the tears that moisturize this whole device. Moreover, this liquid washes dirt and protects against pathogenic bacteria. Tears are very necessary for our body.