Lasers

Broad Beam Lasers
A broad beam laser uses a relatively large beam diameter (from 6.0 to 8.0 millimeters) that can be manipulated to ablate the cornea. The broad-beam laser results in the shortest procedure time. This speed creates less likelihood of overcorrection and decentration - a complication caused by movement of the pupil. A disadvantage is an increased possibility of center islands - a complication related to ablation. However, ophthalmologists have learned to decrease the incidence of center islands by using several short laser pulses to ablate the cornea instead of one longer one.

Slit Scanning Lasers
A slit scanning laser uses relatively small beams linked to a rotational device with slit holes that can enlarge. During surgery, the laser beam scans across these holes to gradually increase the ablation zone. A uniform beam and potentially smoother ablations characterize slit scanning lasers. Disadvantages include a slightly higher propensity for decentration and slightly greater risk of overcorrection.

Spot Scanning Lasers
These systems have the potential to produce the smoothest ablations and use radar technology to track the eye's movement. They also have the potential to treat irregular astigmatism and link to topography. These lasers must be linked to eye tracking to ensure proper centration.