Wednesday, May 03, 2006

Lasik Eye Surgery

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.
Of course, there are potential problems with LASIK. The three most common problems are:
Undercorrection - Not enough tissue is removed during the procedure.
Overcorrection - Too much tissue is removed during the procedure.
Wrinkling - The corneal flap has a small fold or wrinkle in it when it is replaced, causing a small blurry area in your vision. Under most circumstances, each of these problems is easily corrected with a second surgical procedure. If the undercorrection or overcorrection is very slight, the surgeon will most likely advise the patient not to attempt to refine his or her vision any further. In fact, many recipients of laser eye surgery never achieve normal vision but are able to reduce their corrective-lens prescription significantly.


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