Types of Laser Eye Surgery
Meet Your Eyes
Before we take a look at laser eye surgery, let's take a good look at those eyes of yours.
Structure of the eye
One of the most important parts of your eye when it comes to your vision is the cornea. It's the part on the front that helps focus light to create an image on the retina on the back of the eye, which is then sent to and interpreted by the brain. The cornea works a bit like a lens on a camera, bending and focusing light to make a clear image.
The cornea—just like any other part of the human body—is not always perfectly shaped. When the cornea is misshaped, or has what's technically referred to as “refractive errors,” the image that you see will appear blurry or out-of-focus.
There are three types of refractive errors:
- Myopia or near-sightedness in which distant objects are more out of focus than near objects
- Hyperopia or far-sightedness, the opposite of myopia, in which near objects are more out of focus than distant objects
- Astigmatism refers to any other distortion of the cornea, such as bends or warps, which cause imperfect vision.
- A combination of hyperopia and astigmatism or a combination of myopia and astigmatism are not only possible, but very common.
Laser Eye Surgery can help correct these problems by using a laser to reshape the cornea, correcting its “refractive” imperfections, thereby improving vision.
Types of Laser Eye Surgery
Lasik is the most familiar and popular form of laser eye surgery, so much so that it's almost used as a generic term for the procedure. But there are actually several different procedures that a doctor can perform when it comes to using a laser to correct your vision.
You can impress people at parties by calling Lasik by its full name: laser-assisted in-situ keratomileusis. That's a fancy way of saying the laser is helping the doctor to remove a certain amount of corneal tissue, thereby reshaping the cornea and improving vision. As we said before, it is the most popular form of laser corrective eye surgery, used to correct astigmatism, myopia and hyperopia, both with and without astigmatism.
During Lasik, your doctor will cut a “hinged flap” in your cornea, lifting it away from the eye. This allows him or her to get where she needs to go: the tissue underneath that needs reshaping. She then uses a laser to reshape the cornea, flattening or curving it according to where it needs to be corrected. The flap is then folded back into place, healing with a little bit of time.
Costs of Lasik surgery vary widely, but you can generally expect to pay from around $1200 to $2600 per eye.
No, we're not having trouble with our spell-check. Lasek with an “e” is another form of laser eye surgery. You can really impress people by referring to it as laser epithelial keratomileusis.
A Lasek procedure is very similar to Lasik, only during surgery, a much thinner piece of the cornea is lifted away. Lasek is a procedure your doctor may recommend if for some reason or other you can't have Lasik. People who have very thin corneas, for instance, sometimes opt for Lasek. (Your doctor is the one who will best be able to determine the thickness of your cornea and which procedure is right for you.) Some people with thinner corneas choose Lasek over Lasik since it's a less invasive—and seen as a less risky—procedure because it doesn't go as deeply into the tissue bed. You'll sometimes see Lasek referred to as Epi-Lasek.
Drawbacks of the Lasek procedure include slightly more discomfort than Lasik and a longer healing time.
The more precise nature of the Lasek surgery is sometimes reflected in its cost, but it typically runs in a similar price range $1,800 to $2,800 per eye.
PRK was an earlier version of laser eye surgery than Lasik. Although it was once king of the laser eye surgeries, it has slowly become less common as Lasik's unstoppable popularity grows. It is still available, however, and still an option for those considering laser eye surgery.
People with low-to-moderate refractive errors often opt for PRK. In PRK, a thin layer on the surface of the cornea is removed and—unlike Lasek or Lasik—it's never replaced. The exposed surface of the cornea repairs itself over a period of a few days while covered with a sort of “bandage,” a special contact lens. The cornea continues to heal over a period of a few months, during which time the improvement in vision will become more and more noticeable.
People who have PRK generally have one eye done at a time, due to the length and nature of the healing process. One of the reasons that Lasik has surpassed PRK in popularity is because the healing process is faster and more predictable.
ALK or Automated Lamellar Keratoplasty is used in some cases to treat high levels of nearsightedness and mild to moderate farsightedness. As in Lasik or Lasek, a small flap is cut in the cornea. Then, your doctor uses microkeratome to remove material under the flap. ALK usually takes less than one hour. ALK, like PRK, is beginning to decrease in popularity due to better results and faster healing rates possible with the other procedures.
LTK or Laser thermokeratoplasty is a relatively new procedure used to treat farsightedness and astigmatism. The heat of a laser beam is used to shrink and reshape the cornea, rather than removing material. The healing time for LTK is much faster than other forms of corrective eye surgery because the procedure is less invasive to the eye. However, the improvements of LTK do not last as long as those attained with other procedures. In general, about half of the corrective effect had been lost two years post-surgery. The cost is about $1500 - $2500 per eye.
To read more about the risks and benefits of these procedures.