How it works The Excimer laser removes microscopic layers of corneal tissue to change its shape, allowing light rays to focus more directly on the retina. To treat nearsightedness, the cornea must be made flatter. This is accomplished by removing tissue from the center of the cornea. To treat farsightedness, the central cornea must be made steeper. This is accomplished by directing the laser beam to remove tissue from around this area.
Regular astigmatism occurs when light rays are focused at more than one point on the retina.
To treat astigmatism, the cornea must be made more spherical. By changing the pattern of the beam, tissue is removed in one direction more than the other. Candidates must not have had a significant increase in their prescription in the last 12 months. It is important that you have realistic expectations and that your decision is based on facts, not hopes or misconceptions. It cannot correct a condition known as presbyopia, or aging of the eye.