LASIK Results: What to Expect

By Keith Croes; reviewed by Charles Slonim, MD

Laser-assisted in situ keratomileusis (LASIK) has helped millions of people around the world reduce their dependence on glasses or contact lenses. It is, however, an elective surgical procedure with some serious associated risks. And most importantly, it is an elective surgical procedure performed on an otherwise healthy eye in the presence of safe and effective nonsurgical alternatives — that is, glasses and contact lenses.

As someone who may be interested in receiving LASIK, you understandably want to know what to expect.

It's difficult, however, to say conclusively what your outcome may be because there are so many variables involved such as the degree and type of vision correction you need, and the experience of your eye surgeon.

Spectrum of LASIK Complications

Everyone who receives LASIK is exposed to some degree of risk. LASIK is associated with a slight risk of both short- and long-term complications. Although most of these respond well to treatment, and thus eventually cease to be complications, some are less easily handled and, very rarely, can cause permanent problems.

According to guidelines released by the Eye Surgery Education Council (ESEC), fewer than 1 percent of patients who have received LASIK to date have experienced serious, vision-threatening problems. Most LASIK complications can be treated and usually resolve within several months of surgery, the ESEC said.

Among the more serious, vision-threatening complications are infection and LASIK flap problems. The incidence of less-serious complications, such as haze, halos, and glare, is variably reported at up to 5 percent. Studies consistently show that LASIK complications decline as surgeon experience increases. So you definitely can increase your chance of a good outcome by making sure you choose an experienced surgeon.

Complication Targets: FDA and Surgeon Standards Say
Low Incidence of Complications a Must

The eyecare community sets high standards for LASIK success. In order for a laser to be approved for LASIK, the Food and Drug Administration (FDA) expects manufacturers to report an adverse event rate no higher than 1 percent in clinical trials. The FDA definition of adverse event includes a list of specific problems including corneal swelling, flap problems, uncontrolled intraocular pressure, and retinal detachment.

The Council for Refractive Surgery Quality Assurance (CRSQA), which certifies refractive surgeons, requires its members to experience complications such as haze, halos, and glare in no more than 3 percent of their LASIK patients, and vision-threatening complications in no more than 0.5 percent of their LASIK patients.

As a possible LASIK candidate, you should know that your risk of certain complications is very much related to your own special circumstances. That is, you may have a condition related to your general health or your eyes in particular that may increase your risk. As you might expect, you will need to discuss this issue with your eyecare professional. Even under the most ideal situation with a technically flawless surgical procedure, each patient responds to eye surgery differently and each patient heals differently.

Study Designs & Acuity Outcomes

There is no central database of vision results from LASIK. Most of what is known about visual acuity outcomes after LASIK is based on various clinical studies, especially those that the FDA requires the laser manufacturers to perform in order to merit approval.

Most clinical studies of LASIK vision outcomes have a few elements in common. The studies record how many people achieve 20/20 vision or better (so-called "perfect" vision) and how many achieve 20/40 vision or better (the minimum visual acuity required to obtain a driver's license in most states). Most studies also assess how many people have a refractive outcome within a diopter or a half diopter of emmetropia (a zero refractive error). Because vision often changes after surgery — usually for the better — many studies measure vision immediately after surgery, several days later, and at one, three and six months.

Page 2 of 2: Comparing data on LASIK lasers. Also, one way your 20/200 vision can be better than LASIK-corrected 20/40; how well you can expect to see after LASIK

[Page updated May 2007]