Scott M. MacRae, MD, has been correcting vision with laser eye surgery for two decades, but to him the procedure is “still a miracle.”

“It’s pretty neat. The patient who’s been nearsighted for decades sits up minutes after the procedure, looks at the clock on the wall and says, ‘Wow!’ There’s always that 'wow effect' when they realize they can see the clock,” muses MacRae, director of refractive surgery and a professor of ophthalmology at the University of Rochester.

Not everyone is a good candidate for laser eye surgery. Here's what you should know about the most common types and how to find out which might work for you.

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Focusing on three procedures

All laser eye surgeries correct vision by reshaping the cornea, the transparent membrane that covers the eye. Its curve determines how well the eye can focus on objects near and far. Laser surgery can correct near-sightedness (myopia), astigmatism (blurred vision) and some cases of mild far-sightedness. 

Here are three of the most common refractive eye procedures:

LASIK (laser-assisted in situ keratomileusis). To perform this best-known of refractive procedures, a surgeon uses a microkeratome (an oscillating blade) or femtosecond (bladeless) laser to etch a flap in the cornea. He then peels the flap back and uses another laser called an excimer to reshape the cornea.

PRK (photorefractive keratectomy). This precursor to LASIK is best for people with thin corneas. “Instead of making a flap, we remove the surface of the cornea in order to reshape it,” explains MacRae. “Afterwards, we put a bandage contact lens over the eye until the surfaces heals.”

SMILE (small incision lenticule extraction). This is one of the newest types of refractive surgery. A surgeon reshapes the cornea by removing a small disk of tissue through a tiny incision. SMILE has two advantages over LASIK: Since it requires only one laser, it disturbs the corneal surface less. And because there’s no flap, it eliminates the risk a flap will dislocate or fold, which happens to about 1 percent of LASIK patients. It also may prevent dry eye, which occurs in “virtually everybody” who has LASIK surgery, says MacRae.

Most people recover from LASIK and SMILE in about a day, says MacRae. PRK recovery can take up to a week. 

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Are you a good candidate?

It may take just a few minutes for a refractive surgeon to perform a procedure like LASIK. But it takes much longer to determine if a person is a good candidate. Some things you and your doctor will consider: 

  • The shape and thickness of your cornea. If it’s weak (unable to hold its shape, a condition called keratoconus) or too thin, you may not be able to have vision-corrective surgery. The shape of your cornea needs to be stable as well. If it’s constantly changing, “it’s like hitting a moving target and you’ll need re-treatment,” says MacRae. If you’ve had a new prescription in the last year, you may want to wait until you have no more vision fluctuations. 
  • Your medical history. If you take drugs such as steroids or have a condition that affects wound healing, such as diabetes, you may be a poor candidate. Having a dry-eye condition also may eliminate you. (The procedure itself often causes dry eyes, particularly in people with significant near-sightedness who may need extensive corneal reshaping.)
  • Your age. Although surgeons used to turn older adults away, “the age range has expanded,” says MacRae. “Older people can be treated with LASIK or PRK.”
  • Your job and lifestyle. More than 90 percent of people who have LASIK wind up with between 20/20 and 20/40 vision without eyeglasses or contact lenses, according to the American Academy of Ophthalmology (AAO). This means that even after surgery you may have to be prepared to live with less than perfect vision and to still need corrective lenses. “Typically people see as well after LASIK as they do with corrective lenses,” adds MacRae, “but it’s not perfect. In five to ten percent of cases, there’s a refractive error. If you aren’t seeing 20-20, your doctor can fine-tune the error after three months.” 
  • Your financial health. Corrective eye surgery costs $2,000 to $3,000 per eye. Few insurance companies cover it. 

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If you go for it...

Refractive eye surgery generally is painless. It's done using a local anesthetic, which means you’re awake throughout. “You can take anti-anxiety medication beforehand,” says MacRae. “Your eyes may feel scratchy afterwards, but that goes away in eight to twelve hours. The next day, you’re comfortable and functioning.”

Dryness may persist in about a quarter of patients. Most people also experience haloes around bright lights. It’s a result of the healing process and should disappear in a few weeks. Serious complications, such as infection and vision list, are extremely rare.

You can lower the risk of complications by choosing a high quality, experienced surgical team. Rule number one, according to the AAO: Don't be taken in by advertisements that make claims such as, "Throw away your glasses!" or "This laser is ranked highest by the FDA" or "Achieve permanent vision correction with refractive surgery!" 

“The safest way to find a good refractive surgeon is to ask your eye doctor to refer you to one,” says MacRae. “The best practices may cost more, but they will take better care of you and be super-meticulous about what they do. Don’t look for bargains. This is the visual event of your life.” 

Denise Foley is a veteran health writer and a former contributing executive editor at Prevention magazine.