The corneal flap is traditionally created using a blade called a microkeratome. However, this approach is quickly being replaced by the use of a femtosecond laser. Using a laser instead of a blade to create the flap minimizes the risk of infection and induced astigmatism. It also makes flap thickness more predictable.
Wavefront and Corneal Topography
LASIK traditionally involves shaping the cornea to create the same effect that the patient's corrective lenses provide. However, glasses and contacts prescriptions are like shoe sizes; you may ideally need a size 9.25 shoe, but your options are limited to a 9 or a 9.5. Wavefront and corneal topography are two different methods of measuring the corneal surface to detect the most minute irregularities and provide a more customized degree of correction. These techniques can also correct or prevent issues such as glare, halos, and compromised night vision.
The excimer laser is used to reshape the cornea. It vaporizes small amounts of tissue to create the contours necessary to restore focus. Excimer lasers can check the position of the eye more than 200 times per second to ensure that each pulse contacts the cornea in the correct location. Any movement of the eye will automatically stop the laser to ensure patient safety and predictable results.