LASIK / IntraLASIK Correction

Who Benefits Most?

• People with low, moderate and high degrees of nearsightedness
• People with low degrees of farsightedness
• People with low, moderate and high degrees of astigmatism

Specific Advantages of LASIK

• Effective for correcting a wide range of focusing problems
• Fast visual recovery
• Minimal temporary side effects
• Permanent tissue modification for lasting correction
• A combination of well established flap creation and Excimer laser ablation technologies

Laser In Situ Keratomileusis (LASIK) is a laser surgical procedure effective for correcting most ranges of nearsightedness, farsightedness and astigmatism, except extremely high degrees. LASIK combines corneal flap surgery with excimer laser reshaping for dramatic results and rapid visual recovery.

LASIK was first performed in the early 1990s in Greece, but the two main components of the surgery were performed separately long before then. South American surgeons began developing corrective procedures in the 1960s by removing a portion of corneal tissue, reshaping it, and then placing it back on the eye. Excimer laser correction has been done on the surface of eyes since 1987. Combining the advanced forms of both types of technology gives LASIK certain advantages for correcting vision.

In 1995, Gimbel Eye Centre surgeons were the first to provide LASIK corrective surgery in western Canada, and in 2005, Gimbel Eye Centre surgeons were the first to perform IntraLASIK, also known as the IntraLase Method of LASIK, in western Canada. For the procedure, the patient sits in a surgical chair which reclines into a horizontal position. A surgical assistant instills topical anesthetic drops to numb 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.

During LASIK surgery, a flap is created in the outer layers of the cornea, using either the IntraLase FS laser or a microsurgical instrument called a microkeratome. The flap is hinged and lifted so the excimer laser can treat only the underlying layer of the cornea. Traditionally, the instrument used for creating a flap has been the microkeratome. It cuts and lifts a flap that is approximately 1/4 to 1/3 of the corneal thickness.  This circular flap remains attached to the cornea by a small hinge of tissue. The hinge enables the flap to be lifted away from the central cornea. The excimer laser can then be used to reshape the exposed mid-layer of 
the cornea.

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.

For more information on IntraLase, click here.

For both methods of flap creation, the eye is held firmly with a suction ring, which exerts some pressure and causes vision to black out momentarily.

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 vapourizes 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 laser removes small portions of peripheral tissue to increase the curvature so light can focus within a shorter distance. And 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.

 

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 week 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.

The majority of Gimbel Eye Centre patients achieve full correction in one treatment. For those who do not, a second treatment or enhancement is generally possible. For several months or years 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 may be created or an alternative procedure may be recommended.

LASIK correction is a very safe procedure. When complications do arise, they can generally be effectively treated with further surgery. The low incidence of complications listed here reflects the exclusive Gimbel Eye Centre experience:

• Infection (less than 1/5,000)
  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 (1%)
  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.

While Gimbel Eye Centre has had excellent results and an enviable safety record with microkeratome LASIK, we now consider IntraLase LASIK to be our preferred method. The reasons for this include:

• Safety: Because microkeratome LASIK completely cuts and lifts the flap, if an irregularity occurs, the surgeon has no choice but to deal with the irregularity immediately. However, with IntraLase, since the flap is not separated completely and not lifted immediately, the character and quality of the flap can be judged first. If deemed unsatisfactory, the flap pattern can be left untouched and the IntraLase pattern can be repeated later.
• Stability: Because the IntraLase laser can make a flap more precisely and thinner than a microkeratome flap, there tends to be greater long-term structural stability for the cornea and more room for future treatment, if necessary.
• Comfort: IntraLase flaps induce considerably less dryness after surgery than LASIK flaps made with the microkeratome.
• Optical quality: Results are more predictable and quality of vision appears to be better with IntraLase.

• Haze and Irregular Astigmatism (less than 2%)
  Sometimes, 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 (less than 1%)
  Cells from the protective surface layer of the cornea can get into the incision area and interfere with the healing process. This problem can occur with multiple enhancements and 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 (less than 1%)
  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. Re-treatments may be performed if vision is affected significantly from either of these situations.
  
  
• Interface Inflammation (less than 1%)
  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.