LASIK Eye Surgery
Tired of hassling with your contacts or glasses? Join the millions of Americans enjoying a lifestyle free of contacts or glasses. American Board Certified Ophthalmologist Frank Hwang, MD brings LASIK and years of experience in refractive surgery to Loma Linda University Eye Institute.
Using remarkable laser technology, the cornea can be reshaped to conform to your glasses or contact lens prescription. LASIK, or Laser in Situ Keratomileusis surgery, reduces the need for corrective lenses in just minutes.
Who Should Have LASIK?
Not everyone is an ideal candidate for refractive surgery. LASIK is best performed on people with low, moderate, and high degrees of nearsightedness. However, refractive surgery has also been found effective for correcting low and moderate degrees of farsightedness as well as astigmatism. The ideal candidate for LASIK should meet the following criteria:
- Must be at least 21 years of age
- Maintain stable vision for one year - minor fluctuations may not disqualify you
- Have a correctable vision problem
- Have eyes free of complicating injuries and diseases - individual assessment required.
- Must not be pregnant or nursing
How LASIK Works
LASIK is a laser surgical procedure effective for correcting refractive errors or focusing ability. During the procedure, the patient lies on their back in a horizontal position. A surgical assistant applies topical anesthetic drops to "freeze" the eye for a painless correction. Assistants then carefully drape the patient's face around the eye to ensure a perfectly clean surrounding area for the surgery.
To perform LASIK, the surgeon first creates a flap of tissue on the surface of the eye using a precise cutting instrument, called a microkeratome. The microkeratome cuts through 1/4 to 1/3 of the thickness of the cornea, creating a flap of tissue. This clear flap is lifted up and folded open, to the side or the top of the eye, still securely attached by the "hinge".
In recent years, the IntraLase laser has become available to create a flap using multiple short pulses. These pulses are so close together they create an almost complete separation of the flap from the rest of the cornea, but they do not actually lift the flap. If the flap pattern is judged to be complete and satisfactory, a delicate separation of the flap is performed with a few gentle manipulations using a surgical instrument.
Learn more about IntraLase.
The surgeon then positions the patient's eye under the excimer laser which is programmed to remove microscopic layers of tissue from the internal part of the cornea, called the stroma, under the flap. The cool laser beam vaporizes tissue away, one microscopic layer at a time, without burning or cutting. This tissue does not replace itself after it is removed. Since the excimer laser light is created at a specified wavelength that does not pass through the cornea, no other part of the eye is affected.
To correct nearsightedness, the laser removes central tissue to decrease the curvature, allowing light rays to focus farther back in the eye to reach the retina.
To correct farsightedness, the central cornea is made steeper by removing small portions of peripheral tissue to increase the curvature so light can focus within a shorter distance.
To correct astigmatism, the laser removes tissue in designated areas to equalize the curvatures of the cornea. After the tissue has been removed, the surgeon places the flap back in its original position where it heals into place with no stitches. The cornea has amazing natural bonding qualities. Within a few minutes, the flap adheres to the underlying tissue. The edges of the flap heal over in 12 to 48 hours, with the entire flap gaining adhesive strength as it continues to heal in the following weeks and months. For each eye, the laser application time is usually less than one minute and the whole LASIK procedure around 15 minutes.
What to Expect with LASIK
Visual recovery is rapid after LASIK. Within one or two days, most patients see clearly, with minimal side effects. These quick results are possible because the epithelial membrane on the surface of the eye has not been disrupted, except for a thin line outlining where the flap was created. Most patients experience little or no discomfort following surgery and vision generally stabilizes within one month.
Antibiotic, anti-inflammatory, and moisturizing drops are required for at least a few days after surgery, and patients wear an eye shield at night to protect the eye while sleeping during the initial healing process.
The temporary side effects following LASIK are minimal and are most often limited to slightly drier eyes, minor increases in light scattering, decreased clarity in dim light, and seeing halos around bright lights at night. These effects are most common when the pupil is larger than normal and the correction is high. (LASIK is therefore not recommended for people with the combination of a very large pupil opening and a high focusing problem.) It is rare for these side effects to interfere with normal activities, and they diminish as the eye heals.
Most patients receive full correction in one treatment. For those who do not, a second treatment or enhancement is generally possible. For several months after the initial surgery, the surgeon can use instruments to lift the flap and remove more tissue with the laser to "fine tune" the results. If an enhancement is needed after a longer healing period, another flap can be created or an alternative procedure may be recommended.
Successful outcomes of LASIK vision correction include the following life changing benefits for people with focusing problems:
- Clear vision without the inconvenience and limitations of corrective lenses Increased independence
- Wider field of vision than with glasses
- Reduced fear about losing corrective lenses at critical times
- Expanded career opportunities
- Greatly increased recreational possibilities More natural appearance without glasses
- Eliminate risks associated with long-term contact lens usage
- Can have corrective lens requirements removed from drivers' license
LASIK correction is a very safe procedure. When complications do arise, they can generally be effectively treated with further surgery. The following are the most common, yet rare, complications associated with LASIK:
Infections are very rare, but they can damage the cornea if not resolved with early treatment. They are usually identified early and effectively treated with medications.
Difficulty Creating a Flap
The unusual shape or characteristics of some eyes can make it difficult for a surgeon to create a proper flap, although surgeon skill and microkeratome quality and maintenance are also factors. When difficulties are encountered, they are often resolved with adjustments. However, effective adjustments are not always possible, resulting in the LASIK procedure being discontinued. When discontinued, the procedure is postponed or another corrective option may be recommended.
Haze and Irregular Astigmatism
Sometimes a slight haze or a small amount of uneven astigmatism results from surgery. These problems usually resolve as the eye heals. However, if they do not, they are usually treatable through a second surgery.
Epithelial Growth under the Flap
Cells from the protective surface layer of the cornea can get into the incision area and interfere with the healing process. This problem is resolved by the surgeon gently lifting the flap, removing the interfering cells and then positioning the flap again.
Shifting or Wrinkling of the Flap
Occasionally wrinkles develop during the healing process. This problem usually resolves itself within three to six months. In cases where the flap has significantly shifted, a repositioning is necessary. The surgeon gently lifts the flap and replaces it in the proper position. Retreatments may be performed if vision is affected significantly from either of these situations.
Most LASIK patients show some interface inflammation as a normal part of the healing process. This inflammation is usually self-limiting and requires no treatment. In cases of increased inflammation, medicated drops are used to treat the symptoms.
Refractive Surgery Coordinator
Loma Linda University Eye Institute