LASIK - the acronym for Laser-Assisted In Situ Keratomileusis - is an elective surgical procedure that uses a cool (non-thermal) laser beam to change the shape of the cornea (the clear front surface of the eye) to improve vision.

The LASIK procedure consists of two steps: 

1.      In Step One, the surgeon creates a circular, micro-thin flap of corneal tissue.  This can be done with an instrument called a microkeratome - which uses a disposable surgical blade to create the incision - or it can be performed with a blade-free instrument called the IntraLase laser.  Whichever device is used, a small area of tissue is left untouched at one end of the flap to keep it attached to the eye.

2.      In Step Two, the surgeon folds back the flap and uses an excimer laser to reshape the underlying corneal tissue.  The flap is then returned to its original position, where it seals without stitches.

The excimer laser removes tiny amounts of tissue to flatten the cornea (to correct  nearsightedness), steepen the cornea (to correct farsightedness), and/or make the cornea more symmetrical in shape (to correct astigmatism).