In order to make a decision as to whether LASIK vision correction surgery is a good alternative for you, it is important to understand the potential risks. If performed by an experienced surgeon, the risks are low--it is one of the safest surgeries performed today. In contrast to PRK, most risks in LASIK are related to the creation and re-adhesion of the corneal flap. The trade-off for these risks is fast visual recovery with less discomfort. And, in most cases, LASIK is the easiest procedure to fine tune with an enhancement.

The following are several potential risks and side effects of LASIK:

Undercorrection

It is possible that not all of an individual's prescription will be corrected by the treatment. Some of the original eye prescription may remain; this is called undercorrection. If you are undercorrected, your distance vision will still be improved over your uncorrected pre-treatment vision. If a myopic patient is in the average range of presbyopia, they will still be able to read comfortably without reading glasses. For mild undercorrection, glasses may be prescribed. For significant undercorrection, further treatment (called "enhancement") may be recommended. Another alternative is to wear glasses or hard contact lenses.

Overcorrection

The treatment could correct more of your prescription than intended. This is termed overcorrection. A mild amount of over correction of myopia is usually well tolerated so that distance and reading vision are minimally affected. If a significant overcorrection for myopia occurs, distance vision is blurry, and near vision is also blurry, especially if the patient is in the presbyopic age range (over 40). This condition is hyperopia. For significant overcorrection, further treatment (called "enhancement") may be recommended. Another alternative is to wear glasses or hard contact lenses.

Glare, Halos, Double Vision

Early side effects of any corneal treatment include light sensitivity and glare. These symptoms are usually gone within days of treatment, but they have been reported to last for months. The cause may be due to poor healing of the surface of the cornea, infection, an allergic or toxic reaction to the post-treatment eye drops or surface cells trapped within the layers of the cornea. Another cause may be decentration of the optical center of the procedure compared to the patient's actual visual center. Treatment is directed towards the cause.

Ghost images may also occur, particularly during the early healing phases. As the eye heals, the initial unevenness (or irregularity of the treated cornea) will significantly smooth out so that ghost images or halos are rarely annoying.

If the laser beam is not centered on the patient's cornea, double vision may result. Glasses or contact lenses may reduce or eliminate these symptoms.

Infection

Any vision correction treatment carries risk of infection. After treatment, antibiotics are used to prevent infection, but an infection within the cornea could lead to permanent loss of vision that could be corrected only by a repeat of treatment or a corneal transplant. Our physicians use every precaution to prevent infection at the time of treatment, including the antibiotics that are prescribed after treatment to prevent infection.

Because Laser Vision Correction procedures temporarily break the protective skin (epithelium) of the surface of the cornea, that surface has to heal back over the treated site to give the best possible vision and to restore the protective mechanisms of the eye. If the surface fails to heal properly, there is an increased risk of infection, poor quality of vision and glare. If infection progresses uncontrolled, it is possible that the cornea could melt or perforate making it necessary to perform a repeat treatment or a partial or complete corneal transplant. Permanent corneal scarring and any of the above complications are rare but could lead to permanent vision loss. Other complications may be possible, and you should ask your doctor about them.

Epithelial Ingrowth

Rarely, some of the corneal surface cells (epithelium) may grow beneath the flap created during the LASIK procedure. These cells typically do not create any problem, but occasionally they can cause postoperative blurred vision or irritation. This problem can be easily identified and treated by gently lifting the flap and removing the trapped epithelial cells.

Regression

Regression refers to the tendency of the eye to drift back slightly toward its original prescription. This occurs more commonly in patients who have had PRK but occasionally occurs in patients with higher amounts of myopia, hyperopia, or astigmatism who have undergone LASIK.

If a significant regression does occur, enhancement procedures may be performed to "tune up" the original treatment, provided your cornea is thick enough to allow retreatment. Enhancements for regression are usually performed three to six months following the original procedure to allow time for the patient's new refraction to stabilize. In some cases, glasses for night driving may be all that is needed.

Diffuse Lamellar Keratitis (DLK)

Diffuse lamellar keratitis--also known as the "sands of the Sahara" syndrome--is a general inflammation that sometimes arises between the corneal flap and the underlying corneal stroma.

Diffuse lamellar keratitis (DLK) is an extremely rare inflammatory reaction that leaves small white deposits underneath the corneal flap after LASIK. The cause of this reaction is unknown. Depending on the amount of inflammation, you may have no symptoms or you may note some haziness in your vision.

Prevention requires maintaining a clean interface between these two areas. This is aided by meticulously draping the eyelids with sterile tape to keep the eyelashes out of the surgical field and by irrigating (rinsing) the cornea to remove any debris that may be in the tear film before making the microkeratome cut. When folding back the flap, it is important to try to prevent any unwanted debris from accumulating on the interface surface. Irrigating under the flap following the application of the laser may also help to assure a clean interface.

Despite meticulous surgical technique, sebaceous secretions from the patient's own eyelid border may collect beneath the flap. This is usually of no consequence. Occasionally, microfibers from the sterile drapes or swabs may appear. Airborne particulate fibers are also occasionally seen as well as an occasional metallic fragment from the high speed keratome blade. Fortunately, most particulate matter does not cause problems unless it is in the visual axis. By drying around the edges of the eye, the surgeon insures that when the corneal flap is folded back, it will not be sitting in a pool of dirty fluid.
Postoperatively, a topical corticosteroid (medicated drop applied to the surface of the eye) is used to suppress inflammation. The steroid is applied for one week because diffuse lamellar keratitis peaks two to five days after surgery. Likewise, a single drop of a nonsteroidal, anti-inflammatory eye drop at the conclusion of surgery is essential. It serves to dramatically reduce pain during the first six hours after surgery.

When present, most cases of diffuse lamellar keratitis respond to treatment with corticosteroid drops. More severe cases may require that the surgeon lift the corneal flap and irrigate beneath it to remove the inflammatory cells. When recognized and treated properly, DLK rarely affects the ultimate visual outcome; in rare cases, DLK will cause a loss of best corrected vision.

A different form of lamellar keratitis has recently been reported, central lamellar keratitis or CLK. CLK appears within the first twenty-four to forty-eight hours and results in a severe central collection of inflammatory debris. At times the underlying stroma is also involved. Treatment is similar to DLK. However, vision may be more often affected, resulting in the need for additional enhancements after recovery.

At the time of this writing, the exact causes of DLK and CLK are unknown. Speculation of causative factors include an inflammatory reaction related to the patient's own sebaceous secretions, reactions to methlycellulose drops, antigens from bacteria, and even immune reactions to byproducts of the laser treated cornea.

Infection or Severe Inflammation

Although infection is the most feared complication, it is extremely rare. As with any surgery, it is avoided through proper surgical technique. If it does occur, it manifests itself in the first forty-eight to seventy-two hours after treatment. That is why it is important to avoid any contact with substances that may cause infection, such as eye makeup, hot tubs, and swimming pool water, for the first week. Additionally, it is imperative that you go to all of your follow-up visits, even if everything seems to be fine. You will be using antibiotic drops postoperatively to help prevent infection. Starting these drops two days prior to surgery can further reduce your risk.

Summary

LASIK is the procedure of choice for virtually all but the most extreme myopes and hyperopes. In addition, most degrees of astigmatism can be treated. It is a very precise procedure and allows for accurate enhancements when needed.