How the Eye Works
by on May.13, 2010, under Vision and Eyecare
You close your eyes, you can’t see. You open your eyes, you can see. Beyond that, do you really understand how your eyes work? They really are pretty amazing. Read on and you’ll see why. (Here’s a hint – cameras work much like our eyes!)
Your eye is made up of several parts including the cornea, the iris and the retina. Everything you see with your eyes has been processed by the ophthalmic part of your brain, which tells you what you are seeing.
First, light enters through the cornea very much like light enters the lens of a camera. This helps focus the light toward the back of the eye. Since the cornea is curved, the light that comes through it also gets bent or refracted.
The back part of the eye is a thin layer called the retina. It acts like the film in a camera would. When the refracted light that came through the cornea lands exactly how it is supposed to on the retina, you see a clear picture of what you’re looking at or reading. If this were the camera, you’d get a perfectly focused photograph.
Once the image you’re seeing has hit the retina, the light is changed into electrical impulses and is sent to your brain by way of the optic nerve. Your brain then tells you what you see.
If the light that comes through the cornea lands in front of the retina instead of right on it, you have nearsightedness. That means that objects closer to you are clear, while objects farther away are blurry.
If the light that comes through the cornea lands behind the retina, you have farsightedness so things close to you are blurry but you see clearly when you look farther away.
When you have astigmatism, it means the cornea is irregularly curved. The light coming through the cornea is scattered instead of focused so your vision is distorted at all distances. You can have astigmatism in one eye and not the other, too.
The other word you’ve probably heard a lot is presbyopia. Assuming you had perfect vision, the natural aging process means that when presbyopia hits, you’ll need to start wearing reading glasses. Presbyopia is the condition in which the tiny muscles that move the lens that shifts the light rays start to weaken. This means that the lens stiffens and your eyes lose the ability to change focus as well as they used to. Thus, the reading glasses.
Our eyes are pretty amazing. Hopefully, you are getting your eyesight checked regularly. If you do wear glasses or contacts, you might want to consider LASIK surgery. Depending on your individual health, current eyesight and expected results, you could be back to 20/20 vision again.
If you are interested in learning more about your eyesight and LASIK in the Portland, Oregon area, please visit 20/20 Institute today.
