Lasik And Refractive Surgery

LASIK is a surgical procedure for correcting near sightedness (myopia), far sightedness (hyperopia) and cylindrical (Astigmatic) refractive errors. LASIK stands for Laser-Assisted in Situ Keratomileusis.

Procedure of LASIK

During LASIK surgery, a flap is created in the outer layers of the cornea. The flap is hinged and lifted so the excimer laser can treat only the underlying layer of the cornea. 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. A laser can then be used to reshape the exposed mid-layer of the cornea.

The laser is used 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.

While creating the flap, the eye is held firmly with a suction ring, which exerts some pressure and causes vision to black out momentarily.

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 under the flap. The cool laser beam vaporizes tissue away, one microscopic layer at a time, without burning or cutting. This tissue does not completely 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.

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 procedure takes around 15 minutes.