Structure of the human eye

The human eye consists of a simple objective which has two parts. These are the cornea and the lens. The amount of light which enters the eye is controlled by the iris which is located between the cornea and the lens. The pupil is located in the middle of the iris and it dilates and contracts depending on the intensity of illumination and thereby regulates the amount of light which enters the human eye.

Then the light passes through transparent vitreous body and forms inverted image on the light-sensitive retina. The retina is a light-sensitive part of the human eye and represents a sensor or a film in the camera. If we unfolded the retina into a surface it would form a circle of approximate diameter 42 mm which is exactly the diagonal of the film. The retina consists of light-sensitive cells – approximately 130 million rods and 7 million cones. In this case the eye can operate as the 137 megapixels camera. The cones are less sensitive but they are capable of distinguishing colors. The rods are much more sensitive and their task is to provide only black-and-white vision.

For the human eye to operate properly we must not forget to mention some auxiliary organs which also have a huge impact on perfect vision. This category includes ocular muscles which secure movement of the eye itself and thanks to which we can change the direction of our look. Then it is the eye socket which represents osseous shell which contains the eye and its main function is to protect the eyeball and last but not least it is important to mention the eyelids and lachrymal apparatus.

The human eye itself is a very complicated but perfectly operating “machine” thanks to which we can perceive surrounding world. But even a minor damage to the eye or to any of the individual parts of the eye can lead to deterioration of vision. Therefore we should realize that we have only one pair of eyes and it is of vital importance to look after them really carefully.