The Eye and Refractive Errors

To understand why the care of an experienced eye surgeon is essential should the need arise, you first need to understand how your eye works and what its potential needs are. Or, at least it’s fun to know how the eye works so you can sound like Bill Nye the Science Guy at parties, or win a bunch of money on Are You Smarter Than a Fifth Grader?

The Parts of the Eye

To get us started, here is a labeled diagram of the human eye: (Source)

Some Interesting Facts About the Parts of the Eye

• The retina, the large reddish region in the diagram, is actually part of the central nervous system in our bodies for several reasons. For one, the retina and optic nerve grow outward from the brain during embryonic development. Secondly, when images are projected onto the retina, it is then the retina’s job to convey these images in a way that makes sense to the brain. This means the retina is  indirectly responsible for any other nerves impulses that occur after the brain interprets an image.

• The plural form of the word iris is irides. In addition, although it looks as if the black pupil in the center of our eye shrinks or expands according to the amount of light our eyes experience, the pupil is just a hole in the iris, and the iris has muscles that allow it to expand or contract to control the amount of light that enters the eye.
• Color blindness is usually inherited, and in those cases it is caused by a lack of color-sensing cells in the retina. In other words, certain cone cells within the retina tissues are responsible for sensing either red, green, or blue, and if one of those kinds of cells isn’t working properly or they just do not exist in your eye, this causes color blindness, or what you could consider the distortion of colors.

Now, this is all a little bit hard to visualize ( <-- bad pun... again) as you are reading (while wearing glasses perhaps?!), so talking with one of our eye care professionals in person can clear up (I can’t help myself!) a lot of the confusion and help you to better understand why the eye is such a delicate organ that demands high-quality care.

Bill Nye Explains How the Eye Works

If you appreciated the Bill Nye reference earlier, you’ll appreciate this video. Here’s Bill Nye explaining how the eye works:

Common Causes of Poor Vision: Nearsightedness, Farsightedness, and Astigmatism

When you think of your eye, try thinking of a mirror. When the mirror is perfectly shaped, therefore flat, and there are no substances on its surface, you can see yourself clearly. But try looking at yourself with a crinkled piece of tin foil, or with the surface of a pond. The foil is misshapen so your image cannot be properly reflected, and the pond is too murky to see yourself. The foil example relates to common causes of poor vision, like nearsightedness, farsightedness, and astigmatism, while the pond example is like cataracts (see our post about Cataract Awareness Month).

The eye is also often compared to a camera, because when both are working properly, they are able to take in light rays, refract them, and clearly interpret an image. Residue on the lens of the camera, just like on the lens of the eye, will prevent an image from being interpreted clearly. An unclear image will also occur if something inside the camera isn’t working properly, if a piece inside is misshapen so that the image is not refracted correctly. Perhaps the camera has trouble focusing on objects that are far away, making it a “nearsighted” camera. Perhaps the camera has trouble focusing on objects that are very close, making it a “farsighted” camera. And if there is a flaw in the lens, it can affect the camera’s ability to focus on anything, near or far, and that is like astigmatism. 

To learn more about the eye and refractive errors, like the ones mentioned above, contact South Texas Eye Institute today.