Author of this page
Dr Serdal Sanak
Ophthalmic surgeon · Refractive and cataract surgery
Hôpital Delta Chirec, Brussels
Member: ESCRS · SBO · SFO · SAFIR
Femto-LASIK and ICL implants are the two main options to correct high myopia or myopia associated with a particular corneal profile. They are not equivalent alternatives: each answers precise indications. The choice is not left to the patient. It rests on anatomical and refractive criteria objectively measured during the preoperative exam.
This page explains the medical logic that leads to one technique or the other, the criteria that tip the balance, and what each option implies in terms of recovery, cost and follow-up. It is aimed at patients who want to understand the reasons for the choice, before or after their exam.
The choice between Femto-LASIK and ICL is a medical decision, not a matter of patient preference. It rests on precise measurements: corneal thickness, topography, degree of myopia, depth of the anterior chamber, tear film, age, lifestyle. These parameters are gathered during the preoperative exam and guide the choice of one technique or the other.
Femto-LASIK remains the reference technique for low to moderate myopia in patients whose cornea can withstand the procedure. ICL takes over as soon as corneal laser reaches its limits: high myopia, thin cornea, irregular cornea, marked pre-existing dryness. The two techniques are therefore complementary, each with its own indication.
Femto-LASIK is a subtractive surgery. A femtosecond laser creates an ultra-thin flap in the cornea, which is lifted to allow an excimer laser to reshape the tissue underneath. A fine layer of cornea is vaporised to change the curvature of the eye and correct the visual defect. The flap is then repositioned: it adheres naturally within seconds. The cornea is permanently modified.
ICL is an additive surgery. A soft, biocompatible and invisible implant (Implantable Collamer Lens by STAAR Surgical) is inserted through a micro-incision in the cornea and positioned between the iris and the crystalline lens. The cornea is not reshaped: it remains anatomically intact. The correction is carried by the implant itself, which stays in place for life but can be removed if necessary.[1]
Femto-LASIK is indicated when several conditions are met: myopia below -8 to -10 dioptres, a cornea of sufficient thickness to support both flap creation and tissue ablation, a normal topography with no early sign of keratoconus, absent or mild dry eye, and a refraction stable for at least two years. These criteria are largely met in the vast majority of myopic patients who seek refractive surgery.
In these cases, Femto-LASIK offers rapid recovery (functional vision within 24 hours), an excellent success rate (more than 95% reach 20/20 or equivalent), and high predictability of the outcome.[2]
ICL is indicated in several situations where corneal laser is not the best option. The most frequent case concerns high myopia, beyond -8 dioptres. Removing a large amount of corneal tissue to correct such myopia mechanically weakens the cornea and degrades optical quality. ICL, which does not touch the cornea, corrects up to -18 dioptres with a visual quality often superior to laser in these cases.[3]
A cornea too thin, either congenitally or due to a surgical history, also leads to ICL. The rule is to preserve a residual corneal bed of at least 250 microns after the laser ablation. If the thickness does not allow it, ICL takes over.
At-risk corneas fall into the same logic: subclinical keratoconus, asymmetric topography, suspicious shape. Applying laser to an at-risk cornea exposes the patient to postoperative ectasia. ICL avoids this risk by preserving the corneal structure.
Finally, a marked pre-existing dry eye can be worsened durably by Femto-LASIK. ICL causes less postoperative dryness, which often makes it the better option in patients with dry eyes.
Manifest and cycloplegic refraction. The exact degree of myopia, hyperopia and astigmatism, measured at rest and under cycloplegia to eliminate accommodation.
Corneal topography and tomography. Mapping of the shape and thickness of the cornea. Detects subclinical keratoconus and at-risk topographies.
Pachymetry. Measurement of corneal thickness to the micron. Determines whether the cornea can withstand the laser procedure.
Anterior chamber. Measurement of the depth of the space between the cornea and the iris. It must be sufficient to allow safe ICL placement.
Tear film. Assessment of pre-existing dry eye, which may argue against laser.
References
| Criterion | Femto-LASIK | ICL |
|---|---|---|
| Nature of the procedure | Subtractive (removes corneal tissue) | Additive (adds an implant) |
| Cornea | Permanently modified | Intact |
| Reversibility | No | Yes, implant removable or replaceable |
| Myopia range corrected | Up to -8 to -10 D | From -0.5 D to -18 D |
| Corneal thickness | Decisive criterion | Not relevant |
| Postoperative dryness | Moderate, transient risk | Less dryness |
| Functional vision | 24 hours | 24 to 48 hours |
| Cost per eye | 1700 to 2250 € | 2700 to 3500 €, implant included |
High myopia, beyond -8 dioptres, is the case where the question of technique arises most. Myopia is not just a curvature defect: in high myopes, the eye is also mechanically longer, more fragile, with a stretched retina. Visual correction therefore comes with long-term structural implications.
Correcting -10 D of myopia by Femto-LASIK requires removing a significant amount of corneal tissue. The higher the myopia, the more the cornea is thinned by the ablation, with two consequences: first a mechanical weakening that may compromise long-term integrity, and second a degradation of optical quality (aberrations, night halos, contrast). For these reasons, most refractive surgeons today consider ICL as the reference technique as soon as myopia exceeds -8 to -10 D.
ICL corrects up to -18 dioptres with a fully preserved cornea. Long-term studies show higher satisfaction rates and better perceived visual quality in high myopes operated by ICL than by LASIK, particularly in night vision.[3]
Some patients learn at the exam that they cannot be operated on by laser. This is the case for corneas that are too thin, topographies suspicious of keratoconus even at a subclinical level, or corneal profiles at risk of postoperative ectasia.
In the vast majority of these situations, ICL is the alternative. The implant does not touch the cornea, so the corneal criteria that exclude laser do not apply. A patient who cannot be operated on by Femto-LASIK is very often a candidate for ICL, provided the depth of the anterior chamber is sufficient (generally beyond 2.8 mm).
The complementarity between the two techniques makes it possible today to offer a solution to most refractive profiles, including those for which laser alone is insufficient.
Both techniques offer rapid recovery and a return to active life within a few days. The timelines differ slightly depending on the activity.
The next day (D+1): driving possible for most patients, return to work (including screen work), comfortable reading. Vision is functional.
First week: gentle sport (walking, indoor cycling, yoga without inversions) allowed from D+7. Avoid swimming pools, saunas and hot baths for 15 days.
Contact sport: martial arts, boxing, rugby, intensive aquatic sports to be discussed case by case. The corneal flap remains theoretically displaceable by direct trauma. For these profiles, PRK is often preferred from the outset.
Stabilisation: final vision at one to three months depending on the correction.
The next day (D+1): driving possible, vision already sharp. Resumption of light activities.
D+2 to D+3: usual return to work.
First week: gentle sport from D+7. Avoid swimming pools and saunas for 15 days.
Contact sport: wait until D+30. Since ICL is intraocular, the implant is not displaceable by external trauma, but healing of the corneal micro-incision takes a few weeks.
Stabilisation: final vision generally at one month.
Neither Femto-LASIK nor ICL is reimbursed by INAMI in Belgium. Refractive surgery is still considered a comfort surgery by the compulsory health insurance, whatever the technique.
Femto-LASIK: 1700 to 2250 € per eye. Postoperative follow-up to one year is included in this fee.
ICL: 2700 to 3500 € per eye, implant included. Postoperative follow-up to one year is also included. The higher cost is explained by the price of the implant (Implantable Collamer Lens by STAAR Surgical) and by the technical complexity of the intraocular procedure.
Some Belgian supplementary health insurers offer a bonus of 100 to 500 € for refractive surgery, whatever the technique. This bonus must be requested before the operation.
From what degree of myopia should ICL be chosen?
Beyond -8 to -10 dioptres, ICL becomes the reference technique in most cases. Below that, Femto-LASIK remains preferable if the cornea is suitable, being simpler and less costly.
Can an ICL implant be removed later?
Yes. ICL can be removed or replaced if needed. This is an advantage when refraction changes over the years or in anticipation of future cataract surgery. Femto-LASIK, by contrast, modifies the cornea permanently.
Does Femto-LASIK cause more dryness than ICL?
Yes. The corneal flap temporarily affects the superficial innervation of the cornea, which can worsen or reveal dry eye for a few months. ICL leaves the cornea intact and causes less postoperative dryness.
Can the eyes be operated on during pregnancy?
No. Refractive surgery, whether laser or ICL, is contraindicated during pregnancy and breastfeeding. Hormonal fluctuations modify refraction and make preoperative measurements unreliable. One waits for the return to a stable refraction after breastfeeding ends.
Femto-LASIK or ICL after 40: what is the logic?
Both remain possible in a patient still emmetropic for distance. The question of presbyopia must be raised: neither laser nor ICL treats it. After 50 in a hyperopic patient or in high myopia close to cataract, crystalline lens surgery with a multifocal implant (PRELEX) may be more suitable.
Which technique is safer?
Both techniques have an excellent safety profile, with rare complications that are most often reversible when they occur. Safety depends less on the technique itself than on the quality of the preoperative exam and on how well the technique chosen matches the patient's profile.
The preoperative exam gathers all the tests needed for the decision: topography, tomography, pachymetry, cycloplegic refraction, anterior chamber measurement, tear film analysis. At the end of this exam, the technique suited to your profile (Femto-LASIK, PRK, ICL or PRELEX) is presented to you, together with the reasons for the choice and any alternatives. The initial consultation can be followed by the complete exam on the same day, in continuity with the visit.