The acronym LASIK stands for Laser-Assisted In Situ Keratomileusis, and is a procedure that permanently changes the shape of the cornea using an excimer laser. Like other types of refractive surgery, the goal of LASIK is to reshape the cornea, or the clear front part of the eye, so that light traveling through it is properly focused onto the retina, which is located in the back of the eye.
During LASIK, a drop of numbing solution is placed in the patient's eye, the area around the eye is cleaned, and an instrument called a lid speculum is used to hold the eyelids open. A ring is placed on the eye and suction is applied. Next, a microkeratome is attached to the suction ring. The provider will use the microkeratome to cut a flap in the patient's cornea.
Another way of creating the corneal flap replaces the microkeratome with the femtosecond laser. This approach to creating the flap provides a high level of accuracy using an infrared beam of light to precisely separate tissue.
After the flap is created, it is lifted and folded back on its hinge. Then the exposed tissue is dried.
Next, the excimer laser is positioned over the patient's eye, and the patient is asked to stare at a light. This light is not the laser used to remove tissue from the cornea, but rather a light that helps the patient to keep his eyes fixed on a single spot while the laser is in use.
When the patient's eye is in the correct position, the provider uses a laser to remove corneal tissue. A computer controls the amount of laser energy delivered to the eye. Before the start of surgery, the provider will have pre-programmed the computer to remove a particular amount of tissue based on the patient's individual needs. After the pulses of laser energy remove the corneal tissue, the flap is then put back into position.
In most cases, a shield is placed over the eye at the end of the procedure. This shield is designed to protect the eye from injury as the flap heals. This is especially important, since no stitches are used to hold the flap in place.
Immediately after the surgery, the patient's vision is usually somewhat blurry. In most cases, vision will have improved by the morning after surgery, and will continue to clear for some time. Most discomfort is mild, and is felt in the hours immediately following the procedure.