What Exactly is Lasik?

Lasik surgery is basically a procedure that, using laser technology, reshapes you cornea in order to correct various vision problems. The main three conditions that can be corrected by laser surgery are: astigmatism, nearsightedness and farsightedness.

The procedure itself is fast (usually about 15 minutes per eye) and almost entirely painless. It uses an eye drop type of anesthesia and involves two steps:

  1. The laser tool makes a very thin, circular flap in the cornea, which is then folded out of the way by the surgeon.
  2. The cornea under the flap is then reshaped to correct the vision problem by removing microscopic pieces of tissue until the desired shape is achieved. After corneal reshaping is done, the flap is returned to the original position.

While Lasik surgery is approved (and monitored) by the U.S. Food and Drug Administration (the FDA), and is a minimally invasive procedure, it’s still a surgical procedure and as such has potential side effects. We discuss these in more detail on our Procedure pages.

Types of Laser Eye Surgery

While Lasik is the most common type of refractive surgery, there are other laser eye surgery techniques that can be used for specialized circumstances.

PRK – Photorefractive Keratotomy

PRK is the predecessor to today’s more common LASIK procedure. Like Lasik, it uses excimer laser technology. PRK is safe and effective, with outcomes as successful as with LASIK. It was the first type of laser surgery and as such has the most experience behind it.

That said, the recovery process can be more bothersome as there is usually some discomfort involved. With LASIK, a flap of tissue is pulled back from the cornea and that tissue is put back in place as a “bandage” until the cornea heals. With PRK, the outer layer of the cornea is removed completely. Then, the reshape is then done exactly as with LASIK and afterwards a contact lens is placed as a bandage until healing takes place, usually about five days. This is what can cause discomfort.

The primary reason for recommending PRK over LASIK is that some patients have corneas that aren’t thick enough. This will be determined during your initial laser surgery examination.

PRK may also be recommended for patients in certain very active professions where the risk of eye injury is high, which can make the risk of flap damage following LASIK surgery higher.

SMILE – Small Incision Lenticule Extraction

SMILE is a newer laser surgery option that was approved by the FDA in 2016. It can be used to treat nearsightedness and astigmatism.

SMILE uses a femtosecond laser, with is an advanced laser vision correction technology. It very precisely cuts an extremely thin disk of tissue from within the layers of the cornea to change its shape and improve vision. This leaves almost all of the surface of the eye undisturbed. The laser then creates a  small opening in the surface of the eye, from which the cut tissue is removed.

This type of laser surgery is considered minimally invasive because the incision made in the eye’s surface is so small.

As of 2018, SMILE can be used on nearsighted patients, but only under two circumstances:

  1. The prescription is between -1.000D and -8.000D, with or without astigmatism.
  2. The prescription is stable, meaning it hasn’t changed for at least a year.

Z-LASIK

Like LASIK, Z-LASIK works by reshaping the cornea and can correct nearsightedness, farsightedness and astigmatism. Both types of laser surgery have similar high rates of success.

What separates the two is the method by which the corneal flap is created. Traditional LASIK uses a microkeratome (which is a high precision surgical blade) to create the corneal flap. Once the flap is creased, the cornea is reshaped using a laser. Z-LASIK, also known as “bladeless LASIK, uses a femtosecond laser instead of a blade to create the corneal flap.

Other than that, the two procedures are the same.

Recovery and potential complications are mostly similar for both procedures. Z-LASIK has a slightly higher risk for edema, but vision after surgery is typically better and the risk for flap complications is lower. Z-LASIK takes longer to perform and may be less comfortable than LASIK.

Overall, LASIK and Z-LASIK are similar enough as far as complications and results that it’s a toss up as to which is best. It depends upon the individual and is a decision that should be made with your eye doctor as to which is best for you.

Wavefront-Guided LASEK

With this technology, computer imaging is used to create a very exact three dimensional map of the cornea. This is then used to program the excimer laser so that it performs a precise sculpting of each patient’s individual cornea.

This contrasts with conventional LASIK, which uses your vision correction prescription to program the laser.

The map created by Wavefront technology can detect very small abnormalities in the cornea, which makes it possible to correct vision to a greater extent that either conventional LASIK or glasses. This means that a greater percentage of patients achieve 20/20 vision using Wavefront.

LASEK – Laser-Assisted Subepithelial Kreatectomy

LASEK is actually a form of PRK. The main difference is that with PRK, the outer layer of the cornea is completely removed and replaced with a contact lens as a bandage after surgery until the cornea heals.

With LASEK, the outer layer of the cornea is loosened with a diluted alcohol solution. A flap is removed, similar to LASIK but much thinner, and kept attached to a corner of the eye and reattached after surgery. The cornea’s outer layer will then regenerate itself in several days. A special contact lens bandage is used to protect the cornea during the healing period.

As with PRK, the primary advantage of LASEK over LASIK is that it can be used for patients with thin corneas.

Epi-LASIK

With Epi-LASIK, a specialized surgical blade called an “Epi-keratome” creates a very exact, thin sheet of tissue from the cornea, with is then placed to the side. The cornea is then reshaped the same as with LASIK and PRK.

The thin sheet of tissue is then moved back in place to adhere to the cornea (or, in some cases removed) and a soft contact lens bandage is inserted to help heal for about four days.

The advantages of Epi-LASIK include less pain overall, as well as reduced surgery time.

Lasik Pros and Cons

While LASIK isn’t a perfect solution for everyone, it has a history of a high degree of success and patient satisfaction.

There was A 2016 study of satisfaction by Malvina Eydelman, M.D., and several other researchers that studied a large group of patients that were found in the “Patient Reported Outcomes with LASIK” studies done by the FDA. It found that for patients whose vision was corrected to 20/40 or better (the vast majority of LASIK outcomes) the satisfaction was a high level of 88 to 93 on a scale of 1-100.

As with many elective procedures, the pros and cons of LASIK are to a great extent based on your personal perspective as to what’s considered acceptable as far as results and side effects are concerned.

For example, how annoyed are you by having to prep and put in contacts every morning? How about if you have to squint to see much at all before putting on your glasses? Are you willing to accept the costs? How do feel about the procedure and how much post-operative discomfort and inconvenience are you willing to accept?

These are all very personal factors that you should consider. To help you in this analysis, we’ve compiled a list of the most common pros and cons you should bear in mind when considering any laser assisted refractive surgery (such as LASIK).

PROS

  1. LASIK can correct nearsightedness, farsightedness and astigmatism.
  2. You will no longer have to hassle with finding your glasses or putting in contacts that may become uncomfortable at the end of a long day.
  3. LASIK is a quick (15 minutes per eye) procedure.
  4. It has a high success rate, with low complications and a lower chance of blurred vision developing.
  5. It is a simple, outpatient procedure, so no general anesthesia and no overnight stay.
  6. Little pain is involved. The procedure itself is relatively pain-free and numbing drops can be used to ease any post-surgery pain.
  7. There are no bandages or stitches after surgery.
  8. Recovery is fast and most patients return to their normal lives in 48 hours or less.
  9. You vision can show improvement as fast as the next day.
  10. While there are side effects, they occur only about 10 percent of the time and usually go away within two to three months.
  11. Many (but not all) patients obtain 20/20 vision. For those that don’t, an additional procedure called an “enhancement” can usually bring the vision correction to a full 20/20 or close to 20/20.
  12. Modern laser technology is designed to shut off immediately if there are any sudden eye movements during the procedure that may cause injury or error.
  13. LASIK is not limited to a one time procedure. Another surgery can be performed after a minimum of one year if your vision happens to change over time.
  14. While still expensive, costs have come down in recent years due to improvements in technology and the fact that an increasing number of eye care professionals are performing the procedure.

CONS

  1. Not everyone is a candidate for LASIK. If you are under 20 the risk that your cornea will change over time is greater. If you are over 40, the lens in your eyes has become stiffer and the procedure may not be as effective or effective at all.
  2. While the odd of experiencing side effects is low, at 10 percent, they may last as long as three months and include: blurry vision, light sensitivity, itchy eyes, problems with night vision, dry eyes, some discomfort, and glares or halos around light.
  3. While rare, there is a small chance that some side effects might become permanent.
  4. You vision may not be properly, or completely, corrected and you might need to continue wearing glasses or contacts until you can have an “enhancement” surgery.
  5. Overcorrections and undercorrections do occur. When they do, you’ll need to wait a minimum of one year before they can be corrected.
  6. While your vision improves by the next day, the cornea takes longer. If you incur any trauma such as hitting your head, rubbing your eyes, or doing high impact sports, the corneal flap can be dislodged which can lead to serious vision problems.
  7. Your eyes may continue to change and you may need LASIK again, particularly if you have a high glasses or contact lens prescription.
  8. Cost is certainly an issue. Almost all health insurance policies seldom cover LASIK, primarily because they consider it to be an elective procedure..
  9. You may experience “Subconjunctival Hemorrhages”, which are red spots on the white of the eye. These are actually bruises caused by the suction ring used to hold the eye still during surgery. While they can look bad, they do not affect the vision and do not cause pain. They last from a week to a month.
  10. You likely will eventually still need glasses. LASIK is almost always temporary. As you age, the normal progression of deterioration of our lenses will invariably cause your prescription to change. For nearsightedness, the correction needed to see clearly in the distance may require the use of reading glasses for near work. This comes as a surprise to many people.