Femto-LASIK and PRK are the two most widely practised laser techniques for myopia, hyperopia and astigmatism. Beyond a few months they give the same visual quality, but they differ in recovery time and in the corneas they suit.
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.
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.
The essentials about PRK vs Femto-LASIK
Essential difference : PRK without corneal flap (surface work), Femto-LASIK with ultra-thin flap.
Recovery : Femto-LASIK 24h, PRK 7 days for functional vision.
Long-term results : equivalent beyond 5 years according to comparative studies.
Femto-LASIK preferred if : normal cornea, rapid recovery needed, professional life incompatible with a week of discomfort.
Same price : 1700-2250 € per eye for both techniques.
The procedure
What sets the two techniques apart
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.
Femto-LASIK
With corneal flap
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.
Femto-LASIK. The femtosecond laser separates a flap within the corneal thickness and leaves it a hinge, like a page lifted without tearing it out.
PRK. The epithelium, the most superficial layer, is removed over a few millimetres. The corneal thickness stays whole: the laser works on the outer layer.
PRK
On the surface, without flap
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.
Recovery
Recovery is where the two techniques differ most. Femto-LASIK allows functional vision to return as early as the next day. PRK requires a little patience during the first week.
Femto-LASIK
Fast and comfortable
D+1: functional vision, return to work often possible.
First week: slight visual fluctuations, eased with lubricating drops.
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.
Long-term visual quality
Comparative studies conducted beyond five years show no significant difference between PRK and Femto-LASIK, either in precision or stability. For properly selected patients, both techniques give equivalent refractive results at one year. They differ in the route taken to get there.
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.
Long-term mechanical risk
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.[2]
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.
Dry eye
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.[3]
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.
Corneal thickness
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.
The choice in practice
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. The complete exam always precedes the decision.
References
Solomon KD, et al. LASIK World Literature Review: quality of life and patient satisfaction. Ophthalmology. 2009;116(4):691-701.
Iskander NG, Peters NT, Anderson Penno E, Gimbel HV. Late traumatic flap dislocation after laser in situ keratomileusis. J Cataract Refract Surg. 2001;27(7):1111-1114. doi:10.1016/s0886-3350(01)00752-0.
Erie JC, McLaren JW, Hodge DO, Bourne WM. Recovery of corneal subbasal nerve density after PRK and LASIK. Am J Ophthalmol. 2005;140(6):1059-1064. doi:10.1016/j.ajo.2005.07.027.
Frequently asked
What patients often ask
PRK or Femto-LASIK: which is the better technique?
Neither is better in absolute terms. At five years, visual results are equivalent. The choice depends on the profile: corneal thickness, sport practised, dry eye, occupation. The preoperative exam determines the suitable technique.
What is the main difference between PRK and Femto-LASIK?
Femto-LASIK creates a corneal flap to access the tissue to be treated. PRK removes the superficial layer (epithelium) and works directly on the surface. Recovery is faster with Femto-LASIK, but PRK preserves more of the cornea's mechanical integrity.
Is PRK more painful than Femto-LASIK?
PRK causes marked discomfort for 48 hours (tearing, photophobia, foreign body sensation), not pain in the strict sense. Femto-LASIK is almost painless postoperatively. This gap is temporary: at one month, comfort is equivalent.
Why is PRK recommended for contact sports?
The flap created in Femto-LASIK remains theoretically displaceable by direct ocular trauma, even years after the surgery. PRK works directly on the surface: the cornea retains its full mechanical integrity, which makes it the recommended technique for martial arts, boxing, rugby or intensive aquatic sports.
Ophthalmic surgeon · Refractive and cataract surgery
CHIREC Hôpital Delta, Brussels
Graduated from the ULB, trained at CHU de Liège and CHIREC. European Diploma in Ophthalmology (FEBO). Refractive and cataract surgery make up the bulk of my operating activity. Dual specialisation: corneal laser surgery (Femto-LASIK, PRK) and intraocular surgery (ICL, PRELEX, cataract). Consultations in French, Dutch, English, Turkish, Kurdish, Persian and Italian.
