Understand it visually

Phakic ICL implant: where is it placed?

The phakic implant (ICL) slides in front of the natural lens, without removing it. Unlike LASIK, it does not touch the cornea: an option for high myopia or thin corneas.

ICL (phakic implant) or LASIK: for which eyes?

LASIK and ICL are two ways to stop relying on glasses, but they do not work on the same principle. LASIK reshapes the cornea with a laser; the ICL adds an implant inside the eye without touching it. The choice is not made according to a trend, but according to your myopia, the thickness of your cornea, your dry eye and what the assessment reveals. Here is how one option or the other is decided.

Direct answer: ICL or LASIK, how to choose?

Key point. LASIK reshapes the cornea with a laser: it is well suited to moderate myopia and astigmatism with a cornea thick enough. The ICL adds a soft implant in the eye without touching the cornea: it has the edge for high myopia, thin corneas or dry eye. Neither one is superior in absolute terms. It is the preoperative assessment, in particular the topography of the cornea, that decides, on a case-by-case basis.

Two different logics: reshape or add

Understanding the difference in principle sheds light on everything else. LASIK and ICL correct the same flaw, but take two opposite paths. One sculpts the cornea, the other leaves it intact and places a lens inside the eye.

LASIK reshapes the inner surface of the cornea with a laser to modify its curvature and correct vision. It removes corneal material: an adequate corneal thickness is therefore needed to begin with.
The ICL (phakic implant) involves sliding a soft implant between the iris and the natural lens, which stays in place. The cornea is not touched. It is a correction that is added, and that can be removed.

According to the American Academy of Ophthalmology, these two approaches are among the reference techniques of refractive surgery. The choice depends on the anatomy of your eye and on your visual flaw, not on one being superior to the other. To go further, see our dedicated pages on LASIK and on the phakic implant (ICL).

Comparison table: LASIK or ICL

The table below summarizes the clinically relevant differences between LASIK and the phakic ICL implant. Neither is « better » in absolute terms: the choice depends on your eye and is decided at the preoperative assessment.

Criterion	LASIK	Phakic ICL implant
Principle	Reshaping of the cornea with a laser: a little tissue is removed to modify its curvature.	Soft implant placed behind the iris, in front of the natural lens: a lens is added, the cornea is preserved.
Flaws corrected	Myopia, hyperopia, astigmatism.	Myopia (including high myopia), hyperopia, astigmatism.
High myopia	Possible up to a certain degree, depending on corneal thickness.	Particularly suited to high myopia, beyond the limits of LASIK.
Corneal thickness	Must be sufficient: measured at the preoperative assessment.	Not a limiting factor: the cornea is not touched.
Thin cornea or subclinical keratoconus	May constitute a contraindication.	Often preferred, because the cornea is preserved.
Reversibility	No: the removed tissue is permanent.	Yes: the implant can be removed or replaced.
Dry eye	Transient dryness is common, most often resolving.	Lower dryness profile (cornea not cut).
Type of procedure	Laser, outpatient, under local anesthesia (drops).	Intraocular surgery, outpatient, under local anesthesia.
Visual recovery	Often functional as early as the next day.	Rapid recovery after the implant is placed.
Follow-up	Postoperative check-ups.	Postoperative check-ups + regular monitoring (pressure, corneal endothelium).
What decides	The preoperative assessment.	The preoperative assessment.

When is LASIK indicated?

LASIK remains a proven solution for a large share of candidates for refractive surgery. It is aimed primarily at moderate flaws, on a healthy and sufficiently thick cornea. The French Society of Ophthalmology stresses the importance of a complete corneal assessment before any decision, because it is the cornea that determines feasibility.

moderate myopia, hyperopia or astigmatism;
cornea of sufficient thickness and regular shape on topography;
absence of marked dry eye and of corneal disease;
vision stable for at least one to two years.

When these conditions are met, LASIK offers generally rapid visual recovery. But as soon as one of these criteria is missing, for example a cornea that is too thin or high myopia, attention turns to the ICL.

When does the ICL have the edge?

The ICL responds precisely to situations where LASIK reaches its limits. Because it does not remove corneal tissue, it is freed from thickness constraints. It is often the preferred route for high corrections. The American Academy of Ophthalmology presents it as an option suited in particular to high myopia and thin corneas.

High myopia, beyond what LASIK can correct safely;
Thin corneas or borderline shapes, where removing material would be risky;
preexisting dry eye, because the ICL affects the corneal nerves little and dries the eye less;
a wish for a reversible correction: the implant can be removed if necessary.

In return, the ICL requires enough internal space in the eye and a careful examination of the depth of the anterior chamber. Here again, everything is decided on precise measurements, not on generalities.

The preoperative assessment: it is what decides

No serious surgeon chooses between ICL and LASIK before the assessment. It is this thorough examination that guides the decision, by objectively measuring the parameters of your eyes. It is carried out in the office and conditions everything that follows. Without an assessment, no reliable choice.

corneal topography and tomography, which map the shape and thickness of the cornea;
pachymetry, which precisely measures corneal thickness;
analysis of the pupil and of the anterior chamber of the eye;
the exact measurement of the visual flaw and the verification of its stability.

This assessment has another role, sometimes decisive: it can reveal an unsuspected corneal fragility. This is precisely what we address in the next section.

And if the assessment reveals subclinical keratoconus?

This is one of the findings that the assessment helps to avoid, and it is crucial. Subclinical keratoconus is an early deformation of the cornea, often with no symptoms at all, that appears only on topography. Yet LASIK, which thins the cornea, is formally contraindicated in this situation: it could worsen the deformation. For this reason, the French Society of Ophthalmology recommends systematic topography before any refractive surgery.

So what happens if an early keratoconus is detected during the assessment?

LASIK is ruled out, because it would weaken an already fragile cornea;
topographic monitoring is set up to follow progression over time;
if the keratoconus progresses, cross-linking may be offered to stabilize the cornea;
depending on the situation, other correction options are discussed, without ever resorting to surgery that thins the cornea.

Far from being bad news, this screening protects your vision over the long term. It is better to discover subclinical keratoconus before the operation than after. That is the whole point of a rigorous assessment. To learn more about this disease, see our feature on keratoconus.

Reversibility, recovery and follow-up: what to remember?

Beyond the indication, a few practical differences matter in the lived experience. The ICL has the distinctive feature of being reversible: the implant can be removed or replaced, which is not the case with LASIK’s corneal reshaping, which is permanent. Both techniques require regular follow-up after the procedure.

LASIK: visual recovery is often rapid; transient dry eye is common during the first weeks to first months.
ICL: reversible correction; monitoring of intraocular pressure and of the correct positioning of the implant.
In both cases: scheduled postoperative check-ups make it possible to verify healing and the stability of the result.

The choice is therefore discussed by weighing the medical indication, your lifestyle and your expectations. It is not a decision to make alone in front of an online comparison, but in consultation, supported by the assessment.

The journey: from assessment to procedure

The refractive assessment (topography, pachymetry, measurement of the flaw) is carried out at the Cachan office. It is what determines whether you are a candidate, and for which technique. If surgery is chosen, whether a LASIK or the placement of an ICL, it is performed in a specialized facility, in a dedicated surgical environment. The essential thing is to start from a complete and honest assessment, one that also knows when it is better to refrain.

FAQ

Frequently asked questions about choosing ICL or LASIK

Is the ICL reversible?

Yes, it is one of its distinctive features. The phakic implant is placed without touching the cornea or the natural lens, and it can be removed or replaced if needed. LASIK, by contrast, reshapes the cornea permanently. This reversibility of the ICL is one of the criteria taken into account when choosing, but it is not enough on its own to decide.

High myopia: LASIK or ICL?

For high myopia, the ICL often has the edge. LASIK removes corneal material, which becomes limited or even risky when the correction to be applied is large. The ICL, which adds an implant without thinning the cornea, does not have this constraint. The final decision nonetheless depends on the thickness of your cornea and the anatomy of your eye, assessed during the evaluation.

Thin cornea: which option to choose?

A thin cornea generally points toward the ICL. Because LASIK removes corneal thickness, it is not advised when the cornea is already thin, so as not to weaken it. The ICL does not touch the cornea and gets around this problem. It is pachymetry, which precisely measures thickness, that makes it possible to decide during the preoperative assessment.

What happens if the assessment reveals early keratoconus?

LASIK is then ruled out, because it thins the cornea and could worsen the deformation. Topographic monitoring is set up, and cross-linking may be offered if the keratoconus progresses, in order to stabilize the cornea. This screening before the operation protects your vision: it is one of the great benefits of a complete assessment.

Is the operation performed at the Cachan office?

The refractive assessment is carried out at the Cachan office: topography, pachymetry, measurement of the visual flaw. The surgery itself, whether a LASIK or the placement of an ICL, takes place in a specialized facility, in a suitable surgical environment. The assessment remains the key step that determines your eligibility and the best-suited technique.

Is the ICL implant visible once in place?

No. The phakic implant is positioned behind the iris, in front of the natural lens: it is invisible to the naked eye, for you as for those around you. It changes neither the color nor the appearance of the eye.

Can you feel the ICL implant day to day?

No. Once in place, the implant cannot be felt: there is no foreign-body sensation, unlike a lens placed on the cornea. It remains stable inside the eye and requires no handling.

Can you have a LASIK after an ICL, or the reverse?

Yes, the two techniques are not permanently mutually exclusive. A touch-up LASIK remains possible after the placement of an ICL if a supplementary correction is useful, and an ICL can be offered when a LASIK is not indicated. Each situation is reassessed during a new evaluation.

Does the ICL implant have to be removed one day?

Not necessarily: it is designed to remain in place over the long term. It can however be removed or replaced if the correction changes, or when the time comes if a cataract develops with age — the implant is then removed during the cataract operation. The ICL does not exempt you from the usual ophthalmological monitoring.

When can you resume sport and work?

The return is generally rapid after either technique, but the exact timeframes depend on your activity and your healing. Screen work and everyday activities resume quickly; contact or water sports require a cautionary delay. Your surgeon gives you personalized instructions.

Sources

American Academy of Ophthalmology (AAO) — Refractive Surgery, LASIK and Phakic Intraocular Lenses.
Société Française d’Ophtalmologie (SFO) — Refractive surgery and preoperative assessment.
American Academy of Ophthalmology (AAO) — Preferred Practice Pattern, Refractive Errors & Refractive Surgery.
Haute Autorité de Santé (HAS) — Evaluation of refractive surgery techniques.

In summary

ICL or LASIK, there is no universal answer. LASIK reshapes the cornea and suits moderate flaws on a thick cornea; the ICL adds a reversible implant and stands out for high myopia, thin corneas or dryness. It is the preoperative assessment, carried out at the Cachan office, that decides, and that also knows how to rule out the laser if it reveals an early keratoconus. The surgery itself is performed in a specialized facility.

This article is intended for informational and educational purposes. It does not replace a medical consultation. Only an examination by an ophthalmologist can establish a diagnosis and propose care suited to your situation.