Femto-LASIK and PRK are the two most widely practised laser surgery techniques today to correct myopia, hyperopia and astigmatism. Both give excellent results: beyond a few months, the visual quality obtained is equivalent. What distinguishes them is the way they get there.
Femto-LASIK lifts a thin lamella of cornea to apply the laser to the layer underneath, which allows visual recovery within a few hours and immediate postoperative comfort. PRK gently removes the superficial layer of the cornea so that the laser works directly on the surface: recovery is more progressive, but this technique remains the reference for certain corneal profiles or lifestyles.
There is no "better" technique in absolute terms. The right choice depends on the thickness of your cornea, your professional activity, your sports practices and a few other criteria we evaluate together during the preoperative exam. This page helps you understand the differences between the two approaches, so you can approach that consultation with confidence and clarity.
The laser that corrects vision is exactly the same in both cases: an excimer laser, which reshapes the cornea with micrometric precision to modify its optical power. The difference is not the correction itself, but how the tissue to be treated is accessed.
A first laser, called femtosecond, cuts an ultra-thin flap in the cornea. This flap is gently lifted to allow the excimer laser to reshape the tissue underneath. The flap is then repositioned exactly: it adheres naturally within seconds, without any suture.
The epithelium, the superficial layer of the cornea, as thin as cigarette paper, is removed mechanically or chemically. The excimer laser then directly reshapes the exposed surface. A therapeutic contact lens is then placed to protect the eye while the epithelium regenerates naturally in four to five days.
This is where the two techniques most clearly differ. Femto-LASIK allows functional vision to return as early as the next day. PRK requires a little patience during the first week.
D+1: functional vision, return to work often possible.
First week: slight visual fluctuations, eased with lubricating drops.
1 to 3 months: vision permanently stabilised.[1]
First 48 hours: tearing, light sensitivity, foreign body sensation in the eye. Uncomfortable, but not painful in the strict sense.
Day 7: removal of the therapeutic lens, epithelium fully regenerated.
1 to 3 months: vision stabilised. Up to six months for the largest corrections.
Comparative studies conducted beyond five years show no significant difference between PRK and Femto-LASIK, either in precision or stability.[2] For properly selected patients, more than 95% reach 20/20 vision or equivalent, whichever technique is chosen. The difference lies in the path travelled, not the destination.
Night halos and glare may appear in the immediate postoperative period with either technique. They diminish progressively and at three months are residual or totally absent in the vast majority of patients.
The flap created in Femto-LASIK, even perfectly healed, remains theoretically displaceable in case of direct and violent ocular trauma. This eventuality remains exceptional, but it exists, including several years after surgery. PRK, which creates no flap, preserves the full mechanical integrity of the cornea.[3]
For martial artists, boxers, rugby players or intensive aquatic sports practitioners, PRK is therefore systematically recommended. For the vast majority of other profiles, this risk is so low that it does not really weigh on the decision.
Creating the flap in Femto-LASIK severs part of the superficial corneal nerves, which can temporarily worsen pre-existing dry eye. Innervation regenerates progressively, but the delay is longer than with PRK, which preserves more surface nerve fibres.[4]
In case of moderate dry eye detected during the exam, PRK is often preferred. In case of severe dryness, however, neither is indicated outright: the dryness must be treated first, then the situation reassessed.
Femto-LASIK consumes about 100 microns to create the flap, plus the thickness needed for the correction. PRK consumes only the thickness strictly necessary for the correction. For thin corneas or larger corrections, PRK may therefore be the only truly safe laser option. If that is not the case, an alternative solution such as ICL implants should be considered.
Femto-LASIK if: normal corneal thickness, no contact sport, no marked dryness, need for fast recovery (working life not compatible with a week of discomfort).
PRK if: thin or irregular cornea, contact sport, moderate dry eye, regulated profession requiring PRK, or enhancement after previous laser surgery.
Neither if: keratoconus, even subclinical; correction too large for the available thickness; untreated severe dryness. In these cases, ICL implants often offer a suitable alternative.
Neither technique is superior in absolute terms. Both are among the most documented and mature in all of refractive surgery. It is the patient's profile that designates the right answer.
It is the exam that decidesTopography, pachymetry, tear film, history, lifestyle: it is these measurements and this context that designate the appropriate technique. No choice is made without a complete exam.
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