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Laser in Situ Keratomileusis (LASIK)


Article updated and reviewed by Raymond S. Douglas, M.D., Ph.D., Assistant Clinical Professor Ophthalmology, UCLA School of Medicine/Jules Stein Eye Institute/UCLA & Director, Orbital and Ophthalmic Plastic and Reconstructive Surgery, Greater Los Angeles Veterans Administration Hospital on April 19, 2005.

Laser in Situ Keratomileusis (LASIK), also known as Excimer Laser Lamellar Keratomileusis, is a procedure used to treat myopia (nearsightedness), hyperopia (farsightedness), astigmatism (a condition in which the front surface of the cornea of the eye is not spherical) and presbyopia (a condition in which the focusing ability of the eyes is weakened).


First used in 1995, this procedure is becoming a very popular treatment for these common vision problems.

Several advancements have been realized in the field during the last several years. Wavefront technology is the ability to refine the laser contouring of the cornea to not only improve how much a person sees, but also to improve how well they can see. This technologic advancement has often been described as “vision beyond 20/20”. This technology takes into account small imperfections in the cornea and can further refine vision.

Another area of advancement is corneal flap creation. A variety of techniques now exist. One of the newer techniques utilizes a laser to make gas bubbles in the cornea to create a flap. This “all-laser” technique does not use a microkeratome or blade.

Advantages of Laser in Situ Keratomileusis (LASIK)

The advantages of LASIK are:

  • no central haze or scar formation
  • eye stability occurs fast, usually one to three months
  • very quick recovery of vision
  • little or no postoperative pain
  • correction of a full range of myopia
  • repeatability. In the case of undercorrection, LASIK may be repeated by lifting the flap and adding additional laser treatment


Who Is A Candidate For Laser in Situ Keratomileusis (LASIK)?

Candidates for LASIK may experience difficulty wearing glasses and contact lens. Most people have tried contact lens and have difficulty wearing them due to allergies, dryness of eyes, astigmatism or other irritants.

Generally the best candidates have moderate to high levels of myopia (-5.00 to -14.00 diopters). Additionally, the following are generally considered factors in a person's condition that may make it unwise to pursue LASIK:

  • severe dry eye
  • significant lagophthalmos (complete closure of the eyelids over the eyeballs)
  • severe blepharitis (inflammation of the eyelid margins)
  • advanced diabetic retinopathy
  • uncontrolled uveitis (chronic inflammation inside the eye)
  • uncontrolled glaucoma
  • pregnancy and lactation
  • keratoconus (abnormal corneal growth in which both corneas gradually become thinned and conical
  • advanced collagen vascular disease such as lupus erythematosis

NOTE: To be a good candidate for this surgery, you should be able to stare at a fixed object for at least 60 seconds.

What to expect before, during, and after surgery?

Before Surgery

If you decide to go ahead with LASIK surgery, you will need a comprehensive evaluation by your eye doctor to determine if you are a good candidate.

If you wear contact lenses, it is a good idea to stop wearing them before your baseline evaluation and switch to wearing your glasses full-time. Contact lenses change the shape of your cornea for up to several weeks after you have stopped using them depending on the type of contact lenses you wear. If you wear soft contact lenses, you should stop wearing them for 2 weeks before your initial evaluation. If you wear toric soft lenses or rigid gas permeable (RGP) lenses, you should stop wearing them for at least 3 weeks before your initial evaluation. If you wear hard lenses, you should stop wearing them for at least 4 weeks before your initial evaluation.

The day before surgery, you should stop using creams, lotions, makeup and perfumes. These products could increase the risk of infection. Ina addition, your doctor may ask you to scrub your eyelashes for a period of time before surgery to get rid of residues and debris along the lashes.

During Surgery

The surgery should take less than 30 minutes. You will lie on your back in a reclining chair in an exam room containing the laser system. The laser system includes a large machine with a microscope attached to it and a computer screen.

A numbing drop will be placed in your eye, the area around your eye will be cleaned, and an instrument called a lid speculum will be used to hold your eyelids open. Depending upon the type of procedure an instrument will be used to create a flap in the cornea. There may be some mild discomfort very briefly.

The laser will be positioned over your eye and you will be asked to stare at a light. This is not the laser used to remove tissue from the cornea. This light is to help you keep your eye fixed on one spot once the laser comes on. NOTE: If you cannot stare at a fixed object for at least 60 seconds, you may not be a good candidate for this surgery.

When your eye is in the correct position, your doctor will start the laser. At this point in the surgery, you may become aware of new sounds and smells. The pulse of the laser makes a ticking sound. After the pulses of laser energy vaporize the corneal tissue, the flap is put back into position.

A shield should be placed over your eye at the end of the procedure as protection, since no stitches are used to hold the flap in place. It is important for you to wear this shield to prevent you from rubbing your eye and putting pressure on your eye while you sleep, and to protect your eye from accidentally being hit or poked until the flap has healed.

After Surgery

Immediately after the procedure, your eye may burn, itch, or feel scratchy. Both your eyes may tear or water. Your vision will probably be hazy or blurry. Do not rub your eyes. Rubbing your eye could dislodge the flap, requiring further treatment. You should contact your doctor immediately and not wait for your scheduled visit if you experience severe pain, or if your vision or other symptoms get worse instead of better.

During the first few months after surgery, your vision may fluctuate and may take 6 months for the vision to stabilize. You may experience glare, halos or difficulty driving at night.


Do you recommend LASIK to correct this condition?

Am I a good candidate for LASIK?

After surgery, will glasses and/or contact lens still need to be worn?

How many LASIK procedures have you performed?

How many of your patients have experienced complications?

What risks and complications are likely in this case?

Will the problem be cured?

What is the total cost?

Editorial review provided by VeriMed Healthcare Network.