Aging Eye Anatomy and How the Eye Works

A good human eye anatomy diagram can help learn how human sense of sight perceives an object. Our eyes are a complex organ consisting of many parts that give us a sense of sight. Our ability to see depends on the conditions of those parts and how they work together.

Continue reading to learn about the anatomy of the human eye and how the eye works. To get a deeper understanding about how the eye’s parts work together we will use a camera analogy. Finally, you can also find explanation about anatomy of the aging eye and presbyopia condition.

Human Eye Anatomy and How the Eye Works

human eye anatomy

When we look at a tree our eyes processing the light it reflects or emits. The light rays from the tree enter the cornea through the pupil and onto the lens. It then progresses through the pupil and the crystalline lens.

In the role of focusing light rays, the cornea provides about two-thirds of the eye’s focusing power and the lens plays a fine-focusing role. Both of the parts focus the light onto the retina, a delicate tissue that lines the interior walls of the back and sides of the eye. On the retina, the tree image becomes reversed and upside-down.

The central area of the retina is the macula, which provides our best vision. The macula is responsible for your critical focusing vision. We use our macula to stare intensely at an object.

The sensitive retinal tissue then converts the light rays into electrical impulses that are transmitted through the optic nerve, to the back of the brain. Here the electrical impulses are interpreted in an upright tree image.

Human Eye Anatomy and Camera Analogy

human eye anatomy and camera analogyTo understand more about eye anatomy and the process of how the eye sees a tree, let’s use eye and camera analogy.

An automatic camera’s aperture will get smaller when the bright light enters its lens. Similarly, your eyes’ pupils will constrict due to the pupillary light response. Like the camera’s aperture, the pupils adjust light rays entering your vision system.

A conventional camera needs a lens and a film to produce the tree image. In the same way, the eye employs cornea, crystalline lens and vitreous to focus the light on the retina, as a film. While you develop your camera’s film into a positive print, the retina captures the image and sends it to the brain to be developed.

So, if any one or more of these components are not functioning perfectly, the result is a poor tree picture. As with the camera, the eye is only an optical instrument of your visual process. You “don’t see” the tree with your eyes. You actually see the tree with your brains.

Aging Eye Anatomy and Presbyopia Condition

presbyopia eye anatomyBeginning at age 40, the eye anatomy is affected by presbyopia — the difficulty to focus on close objects caused by the natural aging process. The aging process makes the crystalline lens less flexible and the muscles surrounding the lens, which control lens focusing, weak.

The lens can no longer accommodate to increase its power to see near objects clearly. The term accommodate here refers to the thickening ability of eye lens to adjust its focusing distance.

You’ll first notice difficulty reading very fine print books. Print seems to have less contrast or blurred and the eyes become easily fatigued when reading the books. If you don’t have any other eye problems holding reading material at arm length can help you see clearly.


Aging Eye Anatomy and How the Eye Works was last modified: July 16th, 2014 by Marcelli