LASIK stands for Laser-Assisted In Situ Keratomileusis. The prefix "Femto" refers to the laser used for the first step: a femtosecond laser, whose pulses are so brief that they cut corneal tissue without burning it, with micron-level precision.
The procedure consists of two successive steps. The first creates an ultra-thin flap in the cornea, which is lifted to expose the underlying tissue. The second uses an excimer laser, guided by the precise mapping of your eye, to reshape the corneal surface and correct your refractive error. The flap is then repositioned: it naturally adheres to the cornea within seconds, without sutures.
Before the introduction of the femtosecond laser, this flap was created mechanically using an oscillating blade called a microkeratome. The switch to laser has eliminated the main source of variability in this step, which represents a significant safety advance.[1] The laser treatment lasts from a few seconds to about a minute depending on the correction. The procedure is performed under topical anaesthesia with eye drops.
The first hours. Right after the procedure, vision is already improved, often blurry and hazy, but significantly better than before. For the first few hours, it is advised to keep the eyes closed to let the flap adhere.
The next day. The vast majority of patients have functional vision sufficient to resume light activities from day 1. Many return to work the day after the procedure.
The first week. Some fluctuations are possible: vision slightly variable depending on the time of day, fatigue, hydration. Lubricating eye drops are prescribed to maintain comfort.
One to three months. Vision stabilises definitively. The vast majority of patients reach their final result within this time frame.[2]
For correctly selected profiles, the results are among the most predictable in all of refractive surgery. More than 95% of patients reach 20/20 vision or equivalent after the procedure.[3]
Halos and night glare exist in the immediate postoperative period. They gradually diminish over the first few weeks. For the vast majority, they are residual or absent at three months.
A suitable cornea. Flap creation combined with laser ablation requires the cornea to have sufficient thickness. This is the first criterion evaluated during the exam, along with topography and pachymetry.
A myopia stable for at least two years. Operating on a still-progressing myopia means correcting a moving target. Stability is verified using previous prescriptions and confirmed by the exam measurements.
A suitable correction range. Femto-LASIK effectively corrects most common myopia, hyperopia and astigmatism. For very high corrections, ICL implants offer a more suitable alternative.
Absence of keratoconus. Keratoconus, even early-stage or subtle, is an absolute contraindication. The corneal topography of the exam detects it precisely, including in its early forms.[4]
Dry eye assessed. The corneal flap affects superficial corneal innervation, which can temporarily worsen pre-existing dryness. Severe dryness leads to a different technique.
References
Femto-LASIK is the reference technique for laser correction of myopia, hyperopia and astigmatism in eligible profiles. But certain situations are a formal contraindication.
Contact sports (boxing, martial arts, rugby, intensive water sports) represent a contraindication to Femto-LASIK. The procedure creates a corneal flap which, even when perfectly healed, remains a zone of reduced mechanical resistance. A direct eye impact can shift this flap years after the operation. For these profiles, PRK is systematically recommended: it does not create a flap and leaves the cornea mechanically intact.
If you practise a contact sport, this point will be discussed during the initial consultation. In most cases, PRK offers results equivalent to Femto-LASIK for laser myopia correction, with more progressive visual recovery but a stronger cornea in the long term.
Is Femto-LASIK permanent?
For the vast majority of patients operated on before age 40 with a stable correction, the results are durable. Refractive stability (at least two years without change) is an eligibility criterion. Beyond 40 years, the progressive appearance of presbyopia is an independent process that Femto-LASIK does not prevent.
The initial consultation makes it possible to determine, in 45 minutes, whether your corneal, refractive and lifestyle profile is compatible with Femto-LASIK. If not, suitable alternatives (PRK, ICL) will be presented to you. Femto-LASIK remains the most widely used laser myopia technique in the world, but its indication depends on a precise evaluation of each profile.