Vision Correction with LASIK

Laser In Situ Keratomileusis (LASIK) is a laser surgical procedure effective for correcting all ranges of nearsightedness, farsightedness and astigmatism, except extremely high degrees. The most commonly performed vision correction procedure, LASIK is performed on nearly 1 million patients per year. LASIK combines corneal flap surgery with excimer laser reshaping for dramatic results and rapid visual recovery.

LASIK was first performed in the early 1990s in Greece, but the two main components of the surgery were performed separately long before then. South American surgeons began developing corrective procedures in the 1960s by removing a portion of corneal tissue, reshaping it, and then placing it back on the eye. Excimer laser correction has been done on the surface of eyes since 1987. Combining the advanced forms of both types of technology gives LASIK certain advantages for correcting vision.

For the procedure, the patient sits in a surgical chair which reclines into a horizontal position. A surgical assistant instills topical anesthetic drops to numb the eye for a painless correction. Assistants then carefully drape the patient's face around the eye to ensure a perfectly clean surrounding area for the surgery.

During LASIK surgery, a flap is created in the outer layers of the cornea, using either the IntraLase FS laser or a microsurgical instrument called a microkeratome. The flap is then lifted and pulled back so the excimer laser can treat only the middle layer of the cornea. Traditionally, the instrument used for creating a flap has been the microkeratome. It cuts and lifts a flap that is approximately 1/4 to 1/3 of the corneal thickness. This circular flap remains attached to the cornea by a small hinge of tissue. The hinge enables the flap to be lifted away from the central cornea. The excimer laser can then be used to reshape the exposed mid-layer of the cornea.

In recent years, the IntraLase Wavefront laser has become available to create a flap using multiple short pulses. These pulses are so close together they create an almost complete separation of the flap from the rest of the cornea, but they do not actually lift the flap. If the flap pattern is judged to be complete and satisfactory, a delicate separation of the flap is performed with a few gentle manipulations using a surgical instrument.

Wave front - Custom LASIK

The LASIK Procedure

Before the LASIK procedure, your eyes will be anesthetized with eye drops and a speculum will be used to restrict eyelid movement. You will be instructed to fixate on a flashing red light with one eye, while the other eye is taped shut. To perform LASIK, the surgeon first creates a flap of tissue on the surface of the eye. During these few seconds, you may feel some slight pressure, but no pain, and your vision will go dim.

The surgeon then positions the patient's eye under the excimer laser which is programmed to remove microscopic layers of tissue from the internal part of the cornea, called the stroma, under the flap. The cool laser beam vaporizes tissue away, one microscopic layer at a time, without burning or cutting. This tissue does not replace itself after it is removed. Since the excimer laser light is created at a specified wavelength that does not pass through the cornea, no other part of the eye is affected.

To correct nearsightedness, the laser removes central tissue to decrease the curvature, allowing light rays to focus farther back in the eye to reach the retina.

To correct farsightedness, the laser removes small portions of peripheral tissue to increase the curvature so light can focus within a shorter distance.

To correct astigmatism, the laser removes tissue in designated areas to equalize the curvatures of the cornea.

After the tissue has been removed, the surgeon places the flap back in its original position where it heals into place with no stitches. The cornea has amazing natural bonding qualities. Within a few minutes, the flap adheres to the underlying tissue. The edges of the flap heal over in 12 to 48 hours, with the entire flap gaining adhesive strength as it continues to heal in the following weeks and months.

For each eye, the laser application time is usually less than one minute and the whole LASIK procedure around 15 minutes.

After the LASIK Procedure

The Risks of LASIK

The Benefit of LASIK

LASIK FAQ's