|
| |
| Have you ever looked at a written page and it looked blurry? Perhaps, you have taken an eye exam for your driver's license and found that you couldn't read the signs very well. May be you have discovered that, as you are nearing 40, you have to hold books and newspapers farther away to read them. |
| Changes in the shape and size of your eyes can cause problems that affect the way you see elements that are close or far from you. These problems are referred to as refractive disorders. So you go to the Ophthalmolagist or Optometrist and find that you need glasses. And your life is not the same any more! |
| Here are the four common refractive vision problems: |
| Myopia (Nearsightedness) |
| Hyperopia (Farsightedness) |
| Astigmation |
| Presbyopia |
| Myopia (Nearsightedness) |
| In Nearsightedness (Myopia), the light from distant objects gets focused in front of the Retina rather than on it. Myopia happens usually when the eyeball is too long; however, it is sometimes caused by too much focusing power in the lens system. The result is that the person can see close-up objects clearly, but distant objects are blurry. |
|
| Hyperopia (Farsightedness) |
| In Farsightedness (Hyperopia), the light gets focused in back of the Retina rather than on it. See following illustration. Hyperopia usually happens when the eyeball is too short or when the focusing power of the lens system is too weak. The result is that a person can see distant objects fine, but close-up objects are blurry. Hyperopia can by corrected by using a convex lens to concentrate or converge the light so that when it passes through the lens system, it comes to focus on the Retina. |
|
| Astigmation |
| In Astigmatism, the shape of the Cornea or the lens is distorted so that the light comes into two focal points. Imagine that the lens is egg-shaped instead of spherical and that light coming over the top and bottom edges is brought to a different focal point than light coming over the right and left sides. To correct this problem, a lens that is shaped to correct the distorted shape of the eye's lens system is made. |
| Presbyopia |
| In Presbyopia, the Cornea and lens of the eye become less stretchy, and therefore cannot change shape as readily to bring light to a focus on the Retina; this happens naturally as we grow older and is usually observed when people reach their 40s. If you have Presbyopia, you have trouble focusing light from near objects on the Retina. To correct this problem, you might get a pair of bifocal lenses to replace your existing glasses. If you don't already wear corrective lenses, you may be able to simply use reading glasses. |
| |
|
| |
| |