The basis for all laser eye surgery is to reshape the cornea so that it changes the focal point of the eye. Ideally, the focal point is changed so that it focuses perfectly on the retina, just like a normal eye.
myopia (nearsightedness) usually results from the eye being too long. The cornea has a more pronounced curve than a normal eye. Laser eye surgery is great for myopia because it is relatively easy to remove a little of the cornea to flatten out the curve.
Myopia (nearsightedness) usually results from the eye being too long. The cornea has a more pronounced curve than a normal eye. Laser eye surgery is great for myopia because it is relatively easy to remove a little of the cornea to flatten out the curve. Hyperopia (farsightedness) normally means the eye is too short, which means that the cornea needs to curve more to properly focus the light on the retina. Although more intensive than correcting myopia, laser eye surgery can treat hyperopia by reshaping the cornea to make it rounder.
Laser eye surgery works by pulsing a tightly-focused beam of light (laser) onto the surface of the eye. Upon contact with the surface of the cornea, the laser
vaporizes a microscopic portion of the cornea (more on this later). By controlling the size, position and number of laser pulses, the surgeon can precisely control how much of the cornea is removed.
LASIK combines the best features of ALK and PRK (see above). Like ALK, LASIK uses a microkeratome to create a "flap" of the outer corneal tissue that can be folded out of the way and then replaced. Once the flap is folded out of the way, LASIK uses the same Excimer laser used in PRK to reshape the underlying corneal tissue. Then the flap is replaced over the reshaped area and conforms to the new shape.
The great thing about the cornea is how quickly it heals. As soon as that flap is replaced, it begins to naturally seal itself to the rest of the cornea. This approach greatly speeds the overall healing process when compared to PRK, which leaves the reshaped area open.
HOW IS THE PROCEDURE:
You enter the laser room and lie down on a reclining chair below a microscope that is part of the laser. When you look up into the laser you will see a red light with a ring of lights around it. You will be asked to look directly at this "fixation" light while the procedure is performed.
The LASIK procedure usually takes about ten minutes. Numbing eye drops will be used to make your entire procedure painless. Each step of the procedure will be explained to you before it is performed. First one eye will be treated, then the other. The eye which is not being treated will be temporarily covered.
An eyelid holder will be placed between your eyelids to prevent you from blinking. Next, your surgeon will use a highly-refined instrument called a microkeratome to create the corneal flap. For custom LASIK, a laser is used to create the corneal flap. You will feel slight pressure but no discomfort. As a perfectly normal part of this procedure your vision will become dark for a few seconds.
After the flap is created you will be able to see the fixation light again. The protective flap will be folded back and the laser applied to the cornea beneath the flap. Generally, the laser is used for less than one minute. The flap is then folded back into place where it adheres naturally and securely without the need for sutures.
