Lasik

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In this segment, Dr. Joseph Kurstin discusses Lasik surgery with Drs. John, Kathryn and Edward Martin.

Lasik is currently the most popular form of refractive surgery, which is a surgery done on the eyes to improve the vision and eliminate the need for glasses or contact lenses. In a lasik procedure, the cornea, or outer surface of the eye is reshaped with a “cold” laser. It takes about 25 minutes to do both eyes, and is a painless procedure.

There are three main types of refractive errors in the eye:

1. Myopia: or nearsighted - where the person can see up close but distance vision is blurred. These people have a longer than average eye.

2. Hyperopia: or farsighted - distance vision is good, but close vision is blurred. These people have a shorter than average eye.

3. Astigmatism: The cornea is oval shaped instead of round, so both distance and near vision are blurred.

For all of these conditions, lasik can change the curve of the cornea to improve the vision:

1. Myopia - the cornea is made flatter

2. Hyperopia - the cornea is made steeper

3. Astigmatism - the cornea is made steeper in one axis, and flatter in the other to make it more round.

In lasik surgery a thin flap of the cornea is lifted, and the laser is used to treat underneath the flap. This is in contrast to PRK which is another surgery for refractive errors. In PRK, there is no flap made, and the top surface of the cornea is directly ablated to modify the corneal curvature.

As people reach the age of 40, another condition called presbyopia develops. This is when the zonules, which help us to focus at near, start to get stiffer and make it more difficult to read. This is why either reading glasses or bifocals are needed after age 40. When performing lasik for patients over 40, two things can be done. Both eyes can be corrected for distance and the patient will have to wear glasses to read, or one eye can be corrected for distance and one for near, which is called monovision.