LASIK in Paris

Rather than a long text, I wanted you to be able to see, step by step, what happens during the procedure. The simulator below faithfully reproduces the key moments of LASIK: cutting the flap, lifting it, sculpting with the excimer laser, repositioning, and healing.

Understanding your procedure

LASIK · the 6 steps

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© Dr Nahaisi Steven, All rights reserved

Step 1 · Before surgery

Normal cornea

Cross-section of the anterior chamber. The cornea is intact, about 550 µm thick. This is what the laser will reshape.

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Step 1: cutting the flap with the femtosecond laser: 10 seconds

You are lying comfortably, with your eye held open by a small device (to prevent blinking). Before the cut begins, a green light flashes in front of your eye, and I ask you to look at it. You see it come closer and you may feel a sensation of contact. Once the device is in position, gentle suction is applied to keep the eye perfectly in contact with the laser.

You then feel slight pressure, much gentler than with older lasers and never painful. Your vision then dims for a few seconds, 7 to be exact, while the Visumax 800 makes the cut.

Step 2: lifting the flap: 15 seconds

Once the cut is done, the operating bed swivels to bring you under the excimer laser. In position, I gently lift the flap. At this point, you feel slight tugging and see shadows passing across your field of vision: this is the handling of the flap. It is a brief, painless sensation.

Step 3: sculpting with the excimer laser: 2.5 seconds per diopter

The Schwind Amaris 750S then treats the exposed stroma. The treatment time is very short, about 2.5 seconds per diopter of myopia treated. You simply look at a light. You feel nothing.

During this time, you may notice a particular smell, sometimes described as a burning smell. This smell comes from the interaction of the laser with the surrounding air: it has nothing to do with the cornea, which is neither heated nor burned. It is simply a normal physicochemical phenomenon of the laser.

Step 4: repositioning the flap: 30 seconds

Once the sculpting is done, I rinse the surface and then lay the flap back exactly in its original position. It adheres immediately through natural suction, without any stitches. This step takes a few dozen seconds.

The actual laser time is about one minute per eye. But there is the setup, the explanations I give you at each step (I describe in advance what you are going to feel), and the operating room music that keeps me company (I sometimes hum during the procedure). All in all, the time spent in the operating room remains very short: about ten minutes for both eyes.

Step 5: healing

In the days that follow, the epithelium closes over along the peripheral cut line (the “side cut”). This peripheral healing takes a few days, and it is what durably secures the position of the flap. After the first 48 hours, the flap is no longer at risk of shifting in the course of normal life.

LASIK corrects the main refractive errors, within limits defined by corneal safety. The thresholds I apply at the Institut Voltaire are as follows:

These limits are indicative. The final decision depends on the precise characteristics of your cornea and your profile, assessed during the pre-operative assessment.

Corneal criteria for LASIK

Eligibility for LASIK is not just a matter of corneal thickness. It depends on a combination of several parameters:

• Total corneal thickness (pachymetry). The usual safety threshold is about 500 microns.
• Average and maximum anterior corneal curvature (keratometry).
• Posterior corneal curvature, which makes it possible to detect early keratoconus.
• Epithelial thickness and its distribution on the map.
• The residual posterior stromal bed after ablation.
• The percentage of tissue ablated relative to the total corneal volume.
• Your eye habits: repeated rubbing, pressure on the eyeballs during sleep. These are risk factors I take into account.

The residual posterior stromal bed

The residual posterior stromal bed is the thickness of healthy stroma that remains beneath the cut and ablation zone. Its value determines the long-term biomechanical stability of the cornea and the risk of post-operative ectasia, the feared adverse effect of LASIK.

The standard safety threshold is 250 to 280 microns. Personally, I set myself a more cautious limit: 300 microns. This extra margin strengthens long-term safety. When the calculated residual bed would be below 300 microns, I turn to TransPRK, which does not require a flap and therefore preserves more of the stroma.

I always discuss these criteria during the assessment, and I go through the test results with you in detail. It is this assessment that determines the technique best suited to your profile.

The pre-operative assessment: everything you need to know

Ref.: Randleman JB. et al., « Risk assessment for ectasia after corneal refractive surgery », Ophthalmology, 2008. Ambrósio R. Jr. et al., « Integration of Scheimpflug-based corneal tomography and biomechanical assessments for enhancing ectasia detection », J Refract Surg, 2017.

Here I describe the procedure itself. A separate page covers all the practical details: the appointment notice, the prescription, the anti-anxiety tablet, removing contact lenses, arriving at the clinic, changing into surgical attire, going home, the first check-up. I refer you to it for complete preparation.

Surgery day: preparation and practical details

Before the procedure

You take an anti-anxiety tablet about an hour before the procedure. No fasting is needed. On arrival, after the administrative formalities and the final eye images, you are dressed in sterile attire and taken to the pre-induction room.

In the operating room, you lie down comfortably. I instill the anesthetic drops. The surgery is performed under local anesthesia with drops only: no general anesthesia, no injection. A small anti-blink device is put in place to keep the eye open without any effort on your part.

The laser treatment

For each eye, the sequence is as follows: cutting the flap with the Visumax 800 (8 to 10 seconds), lifting the flap, sculpting with the Schwind Amaris 750S (a few seconds), repositioning the flap. The laser follows your eye at all times thanks to its eye-tracking system, even if your gaze drifts slightly.

We then move on to the second eye. The time spent in the operating room is very short: about ten minutes for both eyes. I explain each step as we go, and there is always a little music playing to relax the atmosphere.

The atmosphere in the operating suite at the Institut Voltaire: the pre-operative room (anesthetic drops and sterile attire), the procedure in progress (with music), and the post-operative room (rest, handing over of glasses, snack).

Iris recognition and eye-tracking: safety throughout the procedure

Before each procedure, two measurements are recorded for each of your eyes: the complete aberrometric map (the exact profile of the correction to apply), and a high-resolution photograph of your iris in its natural position, which includes cyclotorsion, the slight rotation of the eye between the sitting and lying positions. These data are then loaded into the laser, separately for the right eye and the left eye.

Just before each laser treatment, the Schwind Amaris 750S performs an iris recognition test: it identifies the unique patterns of your iris and confirms that it is about to treat the right eye, with the right correction profile. This cross-check prevents any mix-up between the right and left eye, or between two patients. On our side, we also make sure through the usual means that we have the right patient in front of us.

The value of this recognition goes well beyond identification safety: the laser adjusts the correction in real time according to the exact position of your iris throughout the procedure. Even if you move your eyes slightly while the laser is sculpting the cornea, which happens naturally, the correction is still applied exactly where it should be. The final result is as precise as if the eye had remained perfectly still.

Right after the procedure

You then go to the recovery room for a short rest, while the first sensations settle. I give you UV-protective glasses and transparent eye shields to wear at night for the first three nights. My secretaries schedule your first follow-up appointment, and I go over the instructions for the first few days again before you leave.

You can go home accompanied, which is what I recommend, or alone by taxi or ride-hailing car (VTC). You will not be able to drive in the hours following the procedure.

LASIK is an extremely well-standardized surgery today, with a very high satisfaction rate. But as with any procedure, there are possible side effects and complications, even if they remain rare. You need to know about them to make a fully informed decision.

Dry eye

This is the most common effect. Dryness is almost always present at first, but temporary. It usually resolves within a few weeks or months with artificial tears. Cases of dryness persisting over several months are rare. I have had a few in practice, and it always eventually settled down, sometimes after 6 months or a year. Dry eye that persists long-term is exceptional.

Physiologically, post-LASIK dryness is explained by the temporary severing of corneal nerve fibers when the flap is cut. These nerves regenerate in 6 months on average. This is a difference from TransPRK, where there is no flap. This difference is not a complication in itself.

I personally see each patient again in consultation, as many times as necessary. In the rare cases of marked dryness, I have a whole range of treatments available: enhanced artificial tears, tear gels in the evening, and sometimes doxycycline tablets in certain predisposed patients (dermatological conditions in particular).

Halos and night vision

Halos around lights, a slight reduction in night vision, and glare may appear in the first weeks, peaking around the 2nd month. This is temporary and gradually fades in almost all patients. At 6 months to 1 year, night vision is usually better than before the procedure.

Imperfect result and enhancement

The result may sometimes not be perfect, or part of the correction may be missing. In that case, an enhancement is sometimes offered, at least six months later. It is not frequent, but it is one of the possibilities planned from the start. Enhancements are simple, lifting the existing flap and readjusting with the excimer laser, and generally make it possible to achieve the intended result.

The enhancement is included in the initial fee during the first year. After that, it is offered at a preferential rate up to 5 years after surgery.

Traumatic flap displacement

This is a very rare risk, which can occur with a direct blow or vigorous rubbing of the eyes in the days following the procedure. That is precisely why we insist on the post-operative precautions: do not rub your eyes, wear the eye shields at night for three nights. After the first 48 hours, the flap can no longer be displaced by rubbing or contact in the course of normal life.

If a displacement occurred in the first few days, we would go back to the operating room to put it back in place. It is a simple procedure. It has happened to me a few times in practice, and the rare patients concerned recovered perfectly. Visual recovery is a little slower in these cases, but with no consequence for the final result.

A violent, badly placed blow could theoretically displace a flap long after the procedure, sometimes even several months later. This is exceptional, to the point that scientific papers are published when it happens. In any case, it would be a blow with the potential to damage the eye even without prior surgery.

And even for these very rare cases, surgically repositioning the flap is possible and allows recovery without lasting effects in most cases.

Serious complications

Infection, corneal ectasia (progressive deformation of the cornea), and lasting loss of visual quality are exceptional events. I have never had to manage one in practice. These complications occur mainly when pre-operative safety criteria have not been strictly followed. As with any surgery, zero risk does not exist. I carry out a complete assessment and remain very selective about eligibility criteria, precisely to minimize these risks.

LASIK touches neither the optic nerve, nor the retina, nor the internal structures of the eye: it does not cause blindness in the usual sense of the word. However, like any surgery, it can in exceptional cases lead to a loss of visual quality, a loss of lines of corrected acuity, significant dryness, or bothersome light phenomena. These situations remain rare, and the purpose of the pre-operative assessment is to reduce these risks as much as possible.

Risks and transparency: everything you need to know

LASIK fee: €3,200 for both eyes (€1,600 per eye). The fee is fixed, the same whatever the correction to be treated, whether myopia, hyperopia or astigmatism.

What is included in the fee

• The procedure itself, using the Visumax 800 and Schwind Amaris 750S lasers.
• Clinic fees at the Institut Voltaire.
• Complete post-operative follow-up, with no limit on consultations.
• Any enhancement during the first year.
• Prescriptions for post-operative medication.

The pre-operative consultation

The pre-operative consultation is charged at the standard rate set by French national health insurance. The arrangements differ depending on the consultation location:

• Offices in the 10th and 19th: nothing to pay upfront (direct billing).
• Institut Voltaire (11th): €50 paid upfront, including a €30 fee supplement. Your complementary health insurance reimburses at least €20, and often the full amount depending on your policy.

Payment

Payment is made on the day of surgery, at the front desk, before the procedure. Accepted payment methods: bank card, check, bank transfer or direct debit. Payment in installments is possible in 4 installments, by check or direct debit.

Complementary health insurance does not pay the clinic directly: you are the one reimbursed on presentation of the invoice. If your complementary health insurance covers a large amount, we can defer a payment corresponding to that sum and only cash it once you have received your reimbursement.

Detailed fees, quotes and insurance reimbursements