Hyperopia occurs when the light rays are not bent enough to focus on the retina.
Regular astigmatism occurs when the light rays are focused at more than one point 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. By changing the pattern of the beam, tissue is more removed in one direction more than the other.