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LASIK Lasers:

LASIK and other forms of laser refractive surgery, such as PRK and LASEK, all use a highly specialized excimer laser to reshape the cornea and correct refractive errors including myopia (nearsightedness), hyperopia (farsightedness) and astigmatism.

Excimer lasers have revolutionized the field of laser eye surgery. And over the decades, advances in excimer laser technology have increased the safety, efficacy and predictability of corneal refractive surgery.

Excimer lasers have the ability to remove, or "ablate," microscopic amounts of tissue from the cornea with a very high degree of accuracy and without damaging the surrounding corneal tissue.

There are several excimer lasers that have been approved by the FDA for use in vision correction surgery performed in the United States, including:

  • STAR S4 IR Excimer Laser System and iDesign Advanced WaveScan Studio System (Abbott Medical Optics) Used in D evi Eye Hospital.
  • Allegretto WAVE Eye-Q Excimer Laser System (Alcon)
  • TECHNOLAS 217Z Zyoptix System for Personalized Vision Correction (Bausch + Lomb)
  • Nidek EC-5000 Excimer Laser System (Nidek)
  • MEDITEC MEL 80 Excimer Laser System (Zeiss)/li>

Though each of these lasers has its own unique set of features, research has shown that all FDA-approved excimer laser produce comparable LASIK results

Most experts agree that your surgeon's skill and experience, and an accurate evaluation of whether you're a suitable LASIK candidate, are far more critical factors affecting final LASIK outcomes than subtle differences between excimer lasers.

How Do Excimer Lasers Work?

Star S4 IR Excimer Laser (Image: Abbott Medical Optics)

The excimer laser emits a cool beam of ultraviolet light of a specific wavelength (typically 193 nanometers) to precisely remove corneal tissue. When the surface of the cornea is reshaped in the right way, it allows light rays to focus properly onto the retina for clear vision.

The high-energy pulses of ultraviolet light penetrate only a tiny amount of the cornea and have the ability to remove as little as 0.25 microns of tissue at a time. (One micron is a thousandth of a millimeter.)

An excimer laser corrects nearsightedness by flattening the cornea; it corrects farsightedness by making the cornea steeper. And astigmatism can be corrected by smoothing an irregular cornea into a more symmetrical shape.

Excimer lasers are controlled by computer settings programmed to correct your specific refractive error. Your surgeon will program the excimer laser with the desired measurements in order to reshape your cornea and treat your prescription. The quantity and pattern of tissue removal are unique to each patient.

Most modern excimer lasers have automated eye-tracking systems that monitor eye movements and keep the laser beam on target during surgery. Studies have shown that eye trackers produce better outcomes and decrease LASIK complications compared with past lasers that did not use eye-tracking systems.

Pupil Size, Ablation Speed And Patient Comfort

In recent years, increasing evidence has indicated that larger pupil sizes may affect laser vision correction outcomes. If your pupil expands in low light beyond the diameter of the laser treatment zone on the cornea, you may experience vision problems such as glare and halos at night.

Some surgeons believe the diameter of the laser ablation should be at least as large as your pupil in dim light. If you have larger pupils, the type of excimer laser may be important in relation to how large the treatment zone (diameter) the laser is capable of creating. You should discuss this with your surgeon.

Treatment times also differ among lasers, ranging from about 20 to 60 seconds or longer, depending on your refractive error. You may consider that important in terms of your comfort as you undergo a procedure.

You also might want to ask whether your surgeon uses a femtosecond laser or a bladed surgical tool (microkeratome) to create the corneal flap in LASIK eye surgery and how these two approaches might differ in terms of your comfort. Many surgeons take opposing sides in the microkeratome vs. femtosecond LASIK debate.

While specific excimer laser technology plays a key role, ultimately it is your surgeon's skill and experience — and your suitability as a candidate — that will be the most important factors affecting your LASIK outcome.

What is laser vision correction?

It is a surgical procedure that uses a cool (non-thermal) beam of light to gently reshape the cornea— the surface of the eye — to improve vision. The laser removes microscopic bits of tissue to flatten the cornea (to correct nearsightedness), steepen the cornea (to correct farsightedness) and/or smooth out corneal irregularities (to correct astigmatism).

The goal of laser eye surgery is to change the shape the cornea so it does a better job of focusing images onto the retina for sharper vision. LASIK and PRK are two types of laser vision correction

Are LASIK and PRK safe?

The FDA recognizes LASIK and PRK as proven, safe and effective, Laser vision correction uses a cool (non-thermal) beam of light that is computer controlled. The surgeon turns the laser on and is able to turn it off at any moment. Many safeguards are in place to reduce the risk of error. However, risks are associated with any surgical procedure.

Studies suggest that the incidence of minor difficulties such as dry eyes and nighttime glare is around 3 percent to 5 percent,. There are no known cases of blindness from LASIK or PRK. Again, outcomes generally are very good.

Can I have both eyes done at the same time?

Most surgeons perform a LASIK procedure on both eyes at the same time. Because it takes longer for clear, comfortable vision after PRK, many surgeons will wait a week or two between eyes for PRK.

How is eye laser surgery different from previous types of refractive eye surgery?

Current FDA-approved laser vision correction methods, such as LASIK (laser-assisted in situ keratomileusis), have a higher predictability of the final result with a lower incidence of complications. Additionally, older techniques typically involved manually performed incisions rather than automated lasers for correction.

Does laser vision correction hurt?

You won't feel pain during LASIK or PRK, because your surgeon will place anesthetic eye drops in your eye first. Afterward, he or she may prescribe pain medication if necessary. Many LASIK patients report no more than mild discomfort for a day or so after surgery. There is more discomfort after PRK because the procedure exposes the deeper layers of the cornea. For clear and comfortable vision after PRK, protective surface cells have to grow back over the treated area. This process can take a week or two, sometimes longer.

How long does LASIK take?

The laser treatment itself usually takes less than a minute, while the entire procedure takes approximately 15 minutes per eye.

How do I know if I'm eligible for laser vision correction?

Your eye care practitioner can help you decide, but here are some general guidelines:

  • You must have healthy eyes — no glaucoma, infection, cataracts, severe dry eye or any other condition that would affect postoperative healing.
  • You must be an adult: age 21 or older (with some exceptions).
  • Your vision must be stable for at least a year before surgery.
  • If you're pregnant or nursing, your hormonal levels can affect the shape of your eye. You'll need to wait until your hormones are back to normal levels.
  • You cannot have a degenerative or autoimmune disease, since this would affect healing.


What happens before laser eye surgery?

Your eye care practitioner will give you a thorough eye exam to make sure your eyes are healthy and you're a suitable candidate for laser vision correction. He or she will test for glaucoma, cataracts and other disqualifying conditions. He or she also will use a machine called a corneal topographer to photograph and electronically map your eye. The surgeon will use this map to plan your surgery for the most precise results possible.

What happens on the day of treatment?

LASIK and PRK are outpatient procedures, which means you'll spend around an hour at the surgeon's office and walk out afterward. Someone else must drive you home, because your vision will be a little blurry right after surgery.

You'll lie down in a reclining chair. The surgeon will place anesthetic drops in your eye, position your head under the laser and place an eyelid speculum (retainer) under your lids to hold your eye wide open.

In LASIK, the surgeon creates a thin flap in the top of the cornea, folds it back out of the way, uses the laser to remove some corneal tissue and then puts the flap back in place. If you're having PRK, no flap is created: The laser simply removes the outer layer of the cornea (epithelium), which grows back after surgery.

What happens afterward?

The surgeon will place eye drops or ointment in your eye. You may relax for a little while then go home and rest. You'll probably notice clearer vision immediately, and typically it will improve even more as the weeks go by.

When may I resume driving?

You may begin driving as soon as you see well enough, excluding the day you had LASIK or PRK performed.

Can I go back to work right away?

Most people who have LASIK return to work after 2 days. With PRK, many surgeons recommend 4 - 5 days of rest instead.

When may I go back to wearing makeup?

You may resume wearing makeup about one week after your surgery. However, throw out your old makeup and buy new to decrease your risk of infection.

Are there any side effects?

Some people experience dry eye after LASIK, which usually is relieved with eye drops and disappears over time. Others may experience starbursts or halos around lights, especially at night. Usually this effect lessens or disappears over time, too.

How many checkups will I need after LASIK?

Depending on your surgeon, you will probably return the next day, then one week or one month later and then three months later. Your doctor will let you know if more visits are necessary.

How much does laser vision correction cost?

There is no one answer regarding what LASIK costs, since fees vary from one surgeon to the next. Prices range from less than 20k- 25k per eye. The average cost for all laser-based vision correction procedures is about 25k per eye. You also can ask your eye surgeon's staff about the possibility of financing a procedure.

I have more questions about LASIK. Who should I ask?

The absolute best source of information about LASIK is a LASIK surgeon, and most provide free consultations. All you have to do is make an appointment.