Lasik Surgery – What Causes Nearsightedness?

Lasik Surgery – taking the mystery out of nearsightedness

Nearsightedness, known as myopia, can be caused by one of two conditions. The cornea or crystalline lens is too powerful or the eyeball is too long and shaped more like an oval than a sphere. Both of these conditions cause the image you are viewing to be projected in front of the retina instead of on the retina, where it belongs for clear vision. Young children with myopia may need stronger and stronger glasses because the length of their eyeball continues to grow as they grow and the images become farther out of focus. Myopia for some adults stabilizes in their late 20s.

People with myopia can not see objects clearly in the distance and their crystalline lens is not able to adjust their focus automatically for them. They are able to see near objects clearly which is where the term nearsighted came from. There are 3 categories of myopia; low myopia, moderate myopia and high myopia. As myopic persons age, those with low myopia may find it easier to read by removing their glasses. But in contrast, those with moderate to high myopia, find their near vision is limited as they age and may need to wear bifocals to read.

For those with moderate to high myopia who elect to have Lasik surgery, they may find that Lasik surgery corrects their distance vision but they may still need bifocals for reading. Many patients find that this is a good trade off because it eliminates the need for wearing glasses or contacts when they drive, go sight seeing on vacation and participate in sports. They only need to wear glasses when they read or do close up work. For most, this is a compromise they are happy to make.

A well shaped cornea allows light to focus through the pupil evenly and the light rays display on the retina in an even pattern. With a normal, but less perfect cornea, the light focuses through the pupil unevenly at varying angles. To correct myopia, the surgeon uses a laser to flatten the corneal curve of the eye to reduce its focusing strength. The laser thins the center of the cornea by vaporizing a small amount of tissue (less than the thickness of a human hair). This change to the cornea, allows the image to be projected on the retina where it belongs. With Lasik surgery, your nearsightedness can be a 'thing of the past'.