Definition : surface laser technique: the treatment is applied directly to the outer layer of the cornea. Photorefractive keratectomy.
Price in Brussels : 1700 to 2250 € per eye.
Recovery : 7 to 14 days for functional vision, 1 to 3 months for complete stabilisation.
Main indications : thin cornea, contact and combat sports, regulated professions (military, firefighters, aircrew), moderate dry eye, retreatment after laser.
Contraindications : keratoconus, need for immediate visual recovery.
Long-term results : equivalent to Femto-LASIK beyond 5 years according to comparative studies.
The technique
How does PRK work?
In Femto-LASIK, a flap is created in the cornea, lifted, the laser treats underneath, then the flap is put back. PRK works directly on the surface. The corneal epithelium, the outermost superficial layer, as thin as cigarette paper, is removed mechanically or chemically to expose the corneal stroma underneath. The excimer laser directly reshapes the surface.
The epithelium grows back naturally in four to five days. During this time, a therapeutic contact lens protects the cornea and reduces discomfort. It is removed during a follow-up appointment seven days after the procedure, once the epithelium has regenerated.
The surface. The epithelium, the most superficial layer, is removed over a few millimetres. The corneal thickness stays whole: the laser works on the outer layer.
The reshaping. The excimer laser works directly on the surface. The epithelium regrows in three to five days, during which vision stays hazy.
The duration of the laser ablation is identical to Femto-LASIK: from a few seconds to one minute depending on the correction. It is the healing that is different. The procedure lasts about ten to fifteen minutes per eye, under topical anaesthesia.
Recovery: what to expect
The first 48 hours. Tearing, photophobia, foreign body sensation, blurry vision. It is not painful in the strict sense, but it is uncomfortable. Prescribed eye drops significantly limit these symptoms. The vast majority of patients describe them as bearable, especially knowing what to expect.
Day 7. Removal of the therapeutic lens. The epithelium has regenerated. Discomfort decreases rapidly. Vision begins to improve but is not yet stable.
The first weeks. Vision fluctuates. It can be good on some days, less sharp on others. This is normal: the cornea is healing and stabilising. You must resist the urge to constantly test your vision.
One to three months. Vision stabilises progressively. For some larger corrections, stabilisation can take up to six months.[1]
Long-term results
Beyond five years, comparative studies show no significant difference between PRK and Femto-LASIK in terms of precision and stability. The difference lies in the path, not the destination.
For myopia up to 6 D and hyperopia up to +3/+4 D, precision is excellent. Beyond that, results remain good but variability increases slightly. Late regressions exist but are rare and generally minimal.
An often overlooked point: mitomycin C
For larger corrections, applying mitomycin C after laser ablation significantly reduces the risk of corneal haze, a slight superficial opacification sometimes observed after PRK. This additional step has become standard in experienced centres.[2]
For whom is PRK the best option?
Thin or irregular cornea. Femto-LASIK requires creating a flap of about 100 microns, then removing tissue for the correction. If the cornea is thin, this double ablation may bring the residual thickness below the safety threshold. PRK, which works only on the surface, preserves more tissue.
Contact sports. The Femto-LASIK flap, even perfectly healed, remains theoretically displaceable by direct and violent trauma. For martial artists, combat sports practitioners and rugby players, PRK eliminates this risk.[3]
Regulated professions. Certain occupations impose restrictions on the type of refractive surgery accepted. PRK is often the recommended or required technique in these contexts.
Moderate dry eye. Creating a Femto-LASIK flap severs the superficial corneal nerves, which can temporarily worsen pre-existing dryness. PRK preserves more corneal innervation.[4]
Enhancement after laser. To improve a result or treat a regression, PRK is often the most suitable technique.
PRK requires patienceRecovery is longer than with Femto-LASIK. That is the only real drawback. Patients who accept it achieve an excellent and durable result, with a mechanically stronger cornea.
References
Alió JL, Muftuoglu O, Ortiz D, Artola A, Pérez-Santonja JJ. Ten-year follow-up of photorefractive keratectomy for myopia of less than -6 diopters. Am J Ophthalmol. 2008;145(1):29-36. doi:10.1016/j.ajo.2007.09.007.
Majmudar PA, Schallhorn SC, Cason JB, et al. Mitomycin-C in corneal surface excimer laser ablation techniques: a report by the American Academy of Ophthalmology. Ophthalmology. 2015;122(6):1085-1095. doi:10.1016/j.ophtha.2015.01.019.
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.
PRK is the reference technique for patients practising contact sports: boxing, martial arts, rugby, intensive swimming. Where Femto-LASIK cuts a flap, PRK treats the surface. The cornea keeps its full mechanical integrity after healing, with no plane of lesser resistance.
It is also the preferred technique for corneas whose thickness is insufficient for Femto-LASIK, and for patients with moderate pre-existing dry eye. Visual recovery is more progressive than with Femto-LASIK (one to two weeks for functional vision, one to three months for complete stabilisation), but the final result is comparable.
Frequently asked questions
What patients often ask
Is PRK safer than Femto-LASIK?
Not safer in absolute terms, but more suitable for certain profiles. It is recommended for thin corneas, contact sports, and pre-existing dryness.
Why is recovery longer with PRK?
The corneal epithelium must regenerate naturally. This process takes four to five days, during which vision is blurry. Stabilisation takes one to three months.
Does PRK leave scars on the cornea?
Sometimes a slight opacification called haze can appear. Applying mitomycin C at the end of the procedure significantly reduces this risk.
Is PRK more painful than Femto-LASIK? The first 48 to 72 hours after PRK are more uncomfortable than after Femto-LASIK: foreign body sensation, tearing, photosensitivity. Painkillers and eye drops are systematically prescribed to manage this phase. Beyond that, recovery is similar.
Can both eyes be done on the same day? Yes, PRK is generally performed on both eyes during the same session. A bandage contact lens is placed at the end of the procedure and removed at the five-day follow-up.
Author of this page
Dr Serdal Sanak
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, with procedures every week at CHIREC Delta. Dual specialisation: corneal laser surgery (Femto-LASIK, PRK) and intraocular surgery (ICL, PRELEX, cataract). Consultations in French, Dutch, English, Turkish, Kurdish, Persian and Italian.
