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Lasik, or Laser-Assisted In Situ Keratomileusis, is the laser vision-correction procedure that is most frequently used worldwide to treat myopia, hypermetropia and/or astigmatism.

Like PRK (photorefractive keratectomy, covered below), the LASIK procedure is based on sculpting the cornea so that the light entering the eye is focused sharply on the retina, improving vision.

The first step is the creation of a thin flap in the cornea with a femtosecond laser (in the 100% laser LASIK procedure). The process lasts about 9 seconds.

Next, an excimer laser is applied to correct the refractive error. The EX500 excimer laser operates at the rate of one diopter per 1.4 seconds. Hence, it takes only 7 seconds to correct a myopia of -5 diopters.

The procedure is painless, and takes about 15 minutes per eye. In almost every case, within less than 24 hours, the vision is corrected. If this procedure is contraindicated, others can be considered, like PRK or intraocular lenses. Your surgeon will guide you through the various vision-correction choices.

Who are the best candidates for LASIK surgery? Anyone with myopia, hypermetropia and/or astigmatism, who does not present a contraindication.

Length of the procedure: +/- 15 minutes per eye

Usual results: 20/20 vision without glasses or contact lenses.

Recovery time: varies, may take a few hours or up to a day.

Common side effects: transient dry eyes and seeing halos around objects at night.

How is LASIK practiced?

LASIK is outpatient surgery. The procedure takes about 30 minutes. Topical local anaesthesia is used in the form of eye drops and the doctor will give you a tranquilizer pill to help you with the pre-surgery anxiety. 

First, a small instrument which keeps the eyelids open is gently placed on the eye.

Next, your surgeon will create a round flap in your cornea, using a femtosecond laser. The flap is then flipped back to expose the deeper layer of the cornea, to which the treatment will be applied. 

The surgeon will then sculpt the curve of your cornea to within a micron, using an excimer laser. Aimed at the cornea, the laser beam pulsates at ultra high frequency, guided by a computer which can detect the slightest micro-movements of your eye, no matter how small they may be. The laser power and aim instantaneously adjust to these micro-movements. However, if the movements are too extreme, the device stops.

Lastly, the flap is put back over the part of the cornea that has just been treated. Sometimes, a contact-lens “bandage” is placed on the eye to protect it for the first 24 hours.

Right after the procedure, you will have time to rest for a little while before you go home. Your surgeon will have prescribed antibiotic and anti-inflammatory eye drops to prevent infection and speed recovery. Just as you would after any surgical procedure, the doctor’s orders must strictly be obeyed to guarantee a good result. Several check-up visits will be scheduled after the procedure, to make sure that you are recovering well.

After the procedure

In the hours immediately after the procedure, your vision may be blurry, but these symptoms usually disappear after the first night of sleep. Within days, your vision improvement will be stabilized, almost instantly. In rare cases, the process may take a few weeks or more. For the vast majority of patients, the result is immediate.

You will probably feel ready to return to work the next day, but we recommend that you rest for a few days. We also advise that you avoid intense physical effort for at least one week.

The procedure is nearly free of risk. However, your surgeon will follow up on your recovery carefully, to detect and treat the slightest complication in time. He or she will pay special attention to lubricating your eyes in the weeks after the procedure. Treatments to prevent dry eyes may be administered.

The long-term results of LASIK

Laser vision-correction procedures can improve the quality of your life considerably. Most patients attain 20/20 visual acuity, and nearly all of them have uncorrected vision of at least 20/40 (the minimum requirement for driving without glasses). There is some possibility that a laser-surgery retouch or pair of glasses/contact lenses will still be necessary after the procedure. But the power required will be much less than before the surgery.

With modern lasers, it isn’t rare for post-operatory eyesight without corrective lenses to be even sharper than pre-operatory vision with corrective lenses.

Post-operatory complications are rare. Side effects like dry eyes or halos around lights in the dark are most often temporary.

However, even after healing, the cornea flap created during LASIK surgery will be a weak part of your cornea in case of trauma. Even several years later, an eye surgeon may re-open it, perhaps to carry out surgical retouching. Likewise, it could be re-opened if the eye were subject to direct impact. For this reason, LASIK surgery is not recommended for people who practice combat sports or dangerous trades, for example. Your surgeon will suggest a PRK treatment if that’s your case.

In rare cases, vision may be unstable over time and require surgical retouching. In cases of presbyopia (far-sightedness due to aging of the eye), a pair of reading glasses may be necessary.