These days, it seems everybody knows somebody who's gotten LASIK eye surgery. But while the vision-correcting procedure is getting more and more common all the time, many prospective patients still find it a little mysterious and more than a little daunting (I mean, corneal carving? Yikes!).

The good news is, you don't have to be an opthamologist to understand the ins and outs of this revolutionary procedure. Below, we put together this handy guide to help you better understand LASIK, so you can decide if the procedure is right for you (just please promise to use your near-perfect vision for good, never evil).

• What is LASIK?
• What happens during LASIK?
• Vision after LASIK?
• Does LASIK hurt?
• Is LASIK safe?
• Is LASIK permanent?
• LASIK Cost
• Am I eligible for LASIK?
• LASIK Side Effects
• PRK vs. LASIK
• LASIK Reviews

What is LASIK? 

LASIK is an outpatient eye-surgery procedure that corrects your eyesight—specifically, nearsightedness, farsightedness, and astigmatism. It stands for laser-assisted in situ keratomileusis. In situ is Latin for "in position." Keratomileusis, a word for this type of surgery, is informative once you know its Greek roots: keras, which means "horn" or "cornea," and smileusis, or "carving." Put it all together and you get laser-assisted positioned corneal carving!

Gulp!

But it's not as scary as it sounds. Basically, LASIK corrects refractive errors by reshaping the cornea to adjust the eye's focusing ability. The result is that you can see more clearly.

What happens during LASIK?

During the procedure, the doctor uses a laser to precisely vaporize microscopic amounts of corneal tissue to reshape the curvature of the cornea based on your precise prescription. Here's what goes down:

1. A surgeon numbs your eyes with anesthetic eye drops. An instrument gently holds your eyes open.
2. As a soft suction ring holds the eye in place—briefly dimming your vision—the surgeon uses a tiny blade or a laser to create a circular flap on the outermost layer of your cornea. The flap acts like a hinged window into the cornea's next layer, called the stroma.
3. Once the corneal flap is lifted and folded back, a different, specialized laser then reshapes the stroma. But it doesn't beam into your eye willy-nilly—it vaporizes certain cells in the stroma according to your exact prescription. You won't feel the laser itself, but you may detect an odor similar to burning hair as the laser ablates corneal tissue.
4. When the laser finishes, the surgeon closes the corneal flap. It will remain shut on its own and heal over time—no weird eye stitches needed. Overall, the procedure lasts for about 10 minutes per eye, and less than a minute of that involves the actual lasering.

What will my vision be like after LASIK?

The American Academy of Ophthalmology (AAO) reports that "more than 90 percent of people who have LASIK achieve somewhere between 20/20 and 20/40 vision without glasses or contact lenses." So LASIK might not get you absolutely perfect vision, but it does typically eliminate dependence on corrective lenses for most everyday tasks.

Patients begin to see more clearly within a few days after their appointment, but some people's vision takes longer (up to six months) to improve and settle at its final acuity. And you still might need to wear glasses or contacts for nighttime driving and similar activities.

Does LASIK hurt?

The surgery itself should be painless. The eyes are numbed beforehand, and the procedure takes about 10 minutes per eye, and again, less than a minute of that involves actual lasering. At most, you'll feel pressure from the lid speculum, which gently holds your eyes open, and the suction ring, which is used when creating the corneal flap.

Since you can't close your eyelids, it isn't possible to mess with the surgery by blinking or winking at a passing hottie. And though you'll be told to look at a light to keep your eye relatively steady, it's okay if it moves a bit. The laser has an advanced tracking system that redirects the beam as the eye moves, and it doesn't target tissue that it's not supposed to.

Is LASIK safe?

Yes. In addition to being FDA approved for reducing dependence on glasses or contact lenses, it is extremely successful for most patients. However, like any surgery, there are risks.

• Pre-surgery screening: Some people are disqualified due to conditions such as chronic dry eye, thin corneas, diabetes, or glaucoma. Prospective patients should inform their doctor of their medical history and get evaluated for any eye conditions.

• Post-surgery complications: Patients may experience dry eyes, sensitivity to light, blurred vision, glare around light sources, and double vision. These effects are temporary and mild for most, but for a small number of cases they become permanent and seriously interfere with daily activities.

Is LASIK permanent?

LASIK cannot be considered totally permanent. Although its effects on the cornea are lifelong, it cannot treat presbyopia, or age-related farsightedness, which generally starts to occur around age 40. So it's not uncommon to need reading glasses even if you've had LASIK.

Additionally, the AAO reports that about 10.5% of LASIK patients in the US require a second treatment—or enhancement—to achieve the desired results. This is more common in those who required more intensive vision correction to begin with.

How much does LASIK eye surgery cost?

Surgeons charge per eye, and LASIK eye surgery cost can vary based on a variety of factors, such as your prescription and the equipment used. TLC Laser Eye Centers says to expect standard prices of about $2,000 per eye. But remember, LASIK is a medical procedure, which means that all sorts of financial help is available. Look into tax-exempt savings accounts such as FSAs and HSAs, or contact your insurance company to see if it offers a discount.

As a reminder, you can also find great deals on LASIK on Groupon, so be sure to check all your options before making a final decision.

Am I eligible for LASIK?

A consultation with an eye doctor will tell you if you're an ideal candidate for LASIK. Typically you'll have to meet the following criteria:

Eyes of suitable quality

During a preoperative exam, the doctor will take detailed measurements of your cornea. Because the surgery revolves around reshaping the cornea (often by ablating microscopic amounts of tissue), it requires healthy corneas of normal thickness. Performing LASIK on corneas that are too thin or misshapen can result in complications.

No preexisting conditions

There are a few conditions that could prevent you from being eligible, including chronic dry eye, glaucoma, cataracts, eye infections or injuries, diabetes, and autoimmune disorders. While some of these will merely delay your surgery until they're treated, others will exclude you altogether. Also, if you're pregnant, breastfeeding, or taking medication that affects your vision, you'll have to wait until your prescription stabilizes.

Vision within a certain range

The eye surgery is most effective on prescriptions within certain limits. This prescription must be stable for at least one year; many doctors prefer two. The following measurements of correction needed to restore normal vision (diopters) are similar to the prescription that appears on your contact-lens boxes:

• LASIK for nearsightedness: Most doctors treat nearsightedness of up to -9D or -10D.
• LASIK for farsightedness: Most doctors treat farsightedness of up to +4D or +5D.
• LASIK for astigmatism: Most doctors treat astigmatism of up to 8D.

What are the side effects of LASIK?

There are mild side effects, but for most patients they're temporary. LASIK's recovery time is fairly short.

The day of surgery

After the procedure, you'll probably experience itchy, burning, and watery eyes—as if they have something small stuck in them—for about 4–6 hours. Your vision will be blurry, so someone else has to get you home. These symptoms can be eased by doctor-prescribed pain medication or eye drops; many patients choose to sleep rather than focus on the discomfort.

The next few days

Most patients find their vision improves enough for them to return to work the day after surgery. Vision may continue to be hazy and feature "halos" or other types of glare, particularly at night.

Three to six months

Follow-up appointments with an ophthalmologist help monitor progress, but in this time period optimal vision improvement should be realized and any LASIK side effects should subside. In rare cases, though, symptoms like dry eye and blurred vision can be permanent.

PRK vs. LASIK: what's the difference?

PRK, or photorefractive keratectomy, is a predecessor to LASIK and therefore very similar. The primary difference is that there is no corneal flap created during PRK. Instead, the cornea's entire outer epithelial layer is removed before a laser alters its stromal layer. This leads to a longer, more painful recovery time as the epithelial layer grows back, but the end results are similar.

Also, PRK is suitable for those with thinner corneas or those who would be at risk for flap complications if they got LASIK. (That latter group includes people who are involved in contact sports and other activities where they could be hit or poked in the eye.)

What are LASIK reviews like?

Check out what some Groupon customers had to say about their LASIK experience:

"Great service from this clinic. The staff were very helpful and knowledgeable. Be prepared to spend minimum 3–4hrs the day of surgery. The procedure itself was pain free and lasted 10 minutes. I was close to 20/20 vision the next day. Great service for the value. I would highly recommend it." – from Milin P.'s review of Vision One Lasik Center in Chicago

"This was a great experience for my husband. We were there for about 3 hours. The office is very nice and the staff were very friendly and inviting. My husband was worried about the quality of work due to the price being way less expensive than what we had been quoted many times before. He wore -4.00 Rx all his life. Immediately he could see 20/20. He was amazed! I will highly recommend Lasik Vision Institute to any and everyone." – from Felicia O.'s review of The Lasik Vision Institute in New York

"They were great. I love having 20/20 vision after years of struggling with glasses. Not sure why I waited so long to get it done." – from John M.'s review of Royo Eye and Laser in Sacramento, CA