What are refractive errors?
In order for our eyes to be able to see, light rays must be bent or refracted by the cornea and the lens so they can focus on the retina, the nerve layer that lines the back of the eye. The retina receives the picture formed by these light rays and sends the image to the brain through the optic nerve.

Normal Eye

What are the different types of refractive errors?

Myopia (nearsightedness) A myopic eye is longer than normal or has a cornea that is too steep, so that the light rays focus in front of the retina. Close objects look clear, but distant objects appear blurred.

Myopia is inherited and is often discovered in children whey they are between 8 and 12 years old. During the teenage years, when the body grows rapidly, myopia may become worse. Between the ages of 20 and 40, there is usually little change. If the myopia is mild, it is called low myopia. Severe myopia is known as high myopia.

In myopia, distant objects appear blurry because the eye is too long, and images focus in front of the retina instead
of on it.

If you have high myopia, you have a higher risk of detached retina. Your ophthalmologist (Eye M.D.) should discuss the warning signs of retinal detachment with you if you are in this risk category. If the retina does detach, a surgical procedure is the only way to repair it. It is important to have regular eye examinations by an ophthalmologist to watch for changes in the retina.

Hyperopia (farsightedness) A hyperopic eye is shorter than normal. Light from close objects, such as the page of a book, cannot focus clearly on the retina. Like nearsightedness, farsightedness is usually inherited. Babies and young children tend to be slightly hyperopic. As the eye grows and becomes longer, hyperopia lessens.

In hyperopia, close objects appear blurry because the eye is too short, and images are not in focus when they reach the retina.

Astigmatism (distorted vision) The cornea is the clear front window of the eye. A normal cornea is round and smooth, like a basketball. When you have astigmatism, the cornea curves more in one direction than in the other, like a football. Astigmatism distorts or blurs vision for both near and far objects. It's almost like looking into a fun house mirror in which you appear too tall, too wide or too thin. It is possible to have astigmatism in combination with myopia or hyperopia.

What is the best method of correcting refractive errors? The Excimer laser reshapes the cornea to create a more focused image on the retina. Glasses and contact lenses do not correct the basic problem. Rather, they attempt to compensate for it by bending light rays into proper focus. Excimer laser procedures reshape the cornea according to an individual's particular prescription to produce the proper focus without "outside help".
There is no best method for correcting refractive errors. The most appropriate correction for you depends on your eyes and your lifestyle. You should discuss your refractive errors and your lifestyle with your ophthalmologist to decide which correction will be most effective for you.