The name "LASIK" is short for Laser In-situ Keratomileusis.  LASIK is used to treat low to high amounts of nearsightedness, astigmatism, and farsightedness.  LASIK combines the computer controlled precision of the Excimer Laser with the benefits of another type of refractive surgery called Lamellar Keratoplasty (a procedure where an instrument known as a microkeratome makes a small flap in the outer layer of the cornea).

The Excimer laser sculpts the internal corneal tissue to the correct refractive power in the "steep" axis by flattening the curvature of the exposed corneal tissue in that axis more than the other. Light rays are then more directly focused on the retina in both axis, thereby reducing the

Astigmatism

In the normal eye, light traveling through the cornea in both the horizontal plane (blue) and vertical (red) plane is refracted (bent) the same, so that the image is properly focused on the retina in the back of the eye. Vision is clear. With astigmatism, an abnormal curvature of the cornea in one direction causes light traveling in one plane, the horizontal (blue) plane in this case, is focused in front of the retina. The light striking the retina through the horizontal plane is out of focus on the retina and vision is unclear.

Treatment

e outer surface of the cornea is treated in such a way with the Excimer Laser as to effectively "flatten" the cornea in the steep axis. In the example above, the steep horizontal axis (blue), is ablated (shaded area) along this axis.

Result After LASIK Surgery For Astigmatism

Before LASIK treatment, light traveling in the horizontal meridian (blue) is out of focus on the retina, in this case. After LASIK treatment, the reshaped cornea (arrow) causes light to bend in such a way as to become focused on the retina. Vision is clear.

Over 96% of patients treated with the LASIK procedure at the Idaho Eye Center are no longer required to wear their glasses or contacts. However, individual results cannot be guaranteed.

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