LASIK and FEMTOLASIK

LASIK: The Most Popular Technique

How it works:

A corneal flap is created with a microkeratome.

Then, the excimer laser reshapes the corneal stroma (middle layer) to correct the visual defect.

Finally, the flap is repositioned without stitches.

Advantages:

Rapid recovery (visual improvement in 24-48 hours).

Minimal postoperative discomfort (mild itching, dryness).

Stable results in a short time.

Disadvantages:

Not recommended for thin or irregular corneas.

Low risk of flap complications (displacement, inflammation).

Ideal for: Patients with thick corneas and moderate refractive errors.

LASIK Treatment Animation

This video is a Zeiss animation illustrating the steps of the LASIK vision correction procedure. The typical surgical steps for this procedure are described below:

Eye Preparation:

Anesthetic drops are applied to numb the eye, and an instrument called a speculum is placed to hold the eyelids open.

Corneal Flap Creation:

The surgeon uses a microkeratome to cut a thin flap in the top layer of the cornea. This flap is carefully lifted to expose the underlying corneal tissue.

Corneal Reshaping:

With the flap lifted, an excimer laser is used to remove precise amounts of corneal tissue and reshape the cornea, thereby correcting refractive problems such as nearsightedness, farsightedness, or astigmatism. Flap repositioning:

Once the reshaping is complete, the corneal flap is returned to its original position, where it adheres naturally without the need for sutures.

This procedure typically takes less than 30 minutes and allows for rapid visual recovery in most patients.

What is FEMTOLASIK?

FemtoLASIK is an advanced refractive surgery technique that uses two types of lasers to correct vision problems (myopia, hyperopia, and astigmatism):

Femtosecond Laser:

Replaces the mechanical microkeratome.

Creates an ultra-precise, customized corneal flap without a blade.

Excimer Laser:

Reshapes the corneal stroma (under the flap) to correct the refractive error.

Advantages vs. Traditional LASIK:

Greater precision (flap thickness controlled to the micron).

Lower risk of complications (no uneven cuts).

Suitable for thin corneas or complex curvatures.

Fast visual recovery (24–48 hours).

2-Step Procedure:

Femtosecond flap creation (20–30 seconds).

Excimer corneal carving (10–30 seconds).

It is the gold standard in refractive surgery due to its safety and predictable results.

FEMTOLASIK with the ATOS (SCHWIND) Femtosecond Laser

Flap Creation in FemtoLASIK with the ATOS SCHWIND Platform

FemtoLASIK surgery uses a femtosecond laser (instead of a mechanical microkeratome) to create a precise, customized corneal flap. The ATOS SCHWIND platform (used in combination with the SCHWIND AMARIS laser) is one of the most advanced for this procedure.

Step-by-Step Flap with ATOS SCHWIND

1. Patient Preparation

Anesthetic drops are applied to numb the eye.

A speculum is placed to prevent blinking.

The system performs eye recognition using corneal topography and eye tracking.

2. Suction and Fixation of the Eye

The ATOS femtosecond laser uses a suction ring to stabilize the eyeball and hold the cornea in position.

This prevents involuntary movements and ensures submicroscopic precision.

3. Femtosecond Laser Flap Design

The laser emits pulses of infrared energy (1,040 nm) in femtoseconds (10⁻¹⁵ seconds), creating plasma bubbles at the level of the corneal stroma.

Customizable parameters:

Flap thickness (usually between 90 and 110 microns).

Diameter (adjusted according to corneal curvature).

Angled bevel for better fit when repositioning.

4. Flap Separation

The surgeon gently lifts the flap with a special spatula, exposing the corneal stroma for excimer laser ablation (SCHWIND AMARIS).

5. Advantages of the ATOS SCHWIND System

Submicroscopic precision (avoids irregularities).

Lower risk of incomplete or decentered flaps.

Customized to corneal anatomy.

Faster recovery vs. mechanical microkeratome.

FEMTOLASIK with the VisuMax 800 Femtosecond Laser (ZEISS)

This video demonstrates the corneal flap creation procedure using the ZEISS VisuMax 800 femtosecond laser, one of the most advanced platforms for refractive surgery (such as FemtoLASIK or SMILE).

Procedure Steps with VisuMax 800

1. Eye Positioning and Suction

Low Pressure Suction Ring:

The VisuMax uses a soft contact system (conical application plane) that adheres to the cornea without excessive compression.

Advantage: Less corneal trauma compared to high-pressure systems.

Monitoring: The laser automatically detects corneal position and curvature.

Fixation with Eye Tracking:

The system follows 6D eye movements (including rotations) to ensure precision.

2. Femtosecond Laser Flap Design

Customizable Parameters:

Flap thickness: Between 90–110 µm (adjustable according to corneal thickness).

Diameter: Adaptable to the patient's anatomy (usually 8.0–9.5 mm).

Bevel: Customized angulation for perfect postoperative closure.

Ultrashort Pulse Technology:

The laser emits femtosecond pulses (10⁻¹⁵ seconds) at a wavelength of 1,040 nm, creating plasma bubbles in the corneal stroma without generating heat.

Visual pattern in the video:

Multiple points of light are observed forming a horizontal plane in the cornea.

The laser acts on deeper layers without affecting the epithelium.

3. Flap Separation

After laser application, the surgeon uses a thin spatula to gently lift the flap and expose the stroma.

VisuMax Key Feature:

The gas bubbles created by the laser are rapidly reabsorbed, allowing immediate manipulation.

Why is it Ideal for Refractive Surgery?

Safe on Thin Corneas:

Allows for the risk-free creation of ultra-thin flaps (90 µm).

Reduced Postoperative Dry Eye:

Low suction preserves corneal nerves.

Versatility:

Used in both FemtoLASIK and SMILE (flapless lenticule extraction).

Why is FEMTOLASIK more expensive than traditional LASIK?

FEMTOLASIK (or 100% laser LASIK) is typically more expensive than conventional LASIK (with a mechanical microkeratome) due to several technological, safety, and operational factors. Here are the main reasons:

1. Advanced (and Expensive) Technology

Femtosecond Laser:

Equipment such as the VisuMax (ZEISS) or Atos (Schwind) has a high acquisition and maintenance cost (can exceed $1 million).

Each laser pulse has a cost per use due to its submicroscopic precision.

Integration with an excimer laser:

Requires combined systems (e.g., SCHWIND AMARIS + ATOS).

2. Greater Precision and Safety

Bladeless corneal flap creation:

Reduces the risk of mechanical complications (e.g., irregular flaps or imperfect cuts).

Allows for customized designs (adjustable thickness, diameter, and bevel).

Lower risk of postoperative dry eye: By preserving more corneal nerve fibers.

3. More Complex Procedure

Two lasers in a single procedure:

Femtosecond (for the flap).

Excimer (for corneal shaping).

Slightly longer surgical time vs. traditional LASIK.

4. Operating and Training Costs

Surgeons require specialized training on advanced laser platforms.

Higher consumption of consumables:

Disposable devices for the femtosecond laser.

Specific solutions and replacement parts.

5. Demand and Perceived Value

Patients often prefer FEMTOLASIK for:

Less invasiveness (no blade).

More predictable results on thin or irregular corneas.

Clinics charge a premium for premium technology.

FEMTOLASIK reduces flap-related complications by 80% vs. mechanical microkeratome (Journal of Cataract & Refractive Surgery).

Why aren't all patients candidates for LASIK or FEMTOLASIK?

Although LASIK and FEMTOLASIK are safe and effective techniques for correcting myopia, hyperopia, and astigmatism, they aren't suitable for everyone. Eligibility depends on anatomical, ophthalmological, and general health factors. Here are the main reasons:

1. Corneal Conditions

Cornea Too Thin

FEMTOLASIK requires a minimum corneal thickness (at least 480–500 microns after trimming).

If the cornea is very thin (or has early keratoconus), the laser could weaken it, causing corneal ectasia (progressive deformation).

Alternatives: PRK (no flap required), SMILE, or intraocular lenses (ICL).

Keratoconus or Irregular Cornea

LASIK/FEMTOLASIK is contraindicated for keratoconus because it can worsen the condition.

Solution: Perform corneal cross-linking first to strengthen the cornea and then evaluate other options.

Corneal Scarring or Opacities

If there is scarring from infections (e.g., ocular herpes) or trauma, the laser cannot work evenly.

2. Unstable Prescription

Myopia, hyperopia, or astigmatism must be stable for at least 1–2 years.

Patients under 21 years of age: Your eyes can still change.

3. Severe Dry Eye

Both LASIK and FEMTOLASIK can temporarily worsen dry eye.

If you already suffer from severe, uncontrolled dry eye, it is best to consider ICL (which does not affect the cornea) or wait to treat the dry eye first.

4. Very Large Pupil (Nyctalopia)

If your pupil dilates more than 7 mm in the dark, LASIK/FEMTOLASIK may cause halos at night or blurred vision in low-light conditions.

5. Eye Diseases

Advanced glaucoma: Elevated intraocular pressure may increase surgical risk.

Cataracts: If the lens is already cloudy, cataract surgery with an intraocular lens is best.

Diabetic retinopathy: Risk of postoperative macular edema.

6. Pregnancy or Breastfeeding

Hormonal changes temporarily alter corneal shape and prescription.

It is recommended to wait 3–6 months after breastfeeding.

7. Systemic Diseases

Autoimmune diseases (lupus, rheumatoid arthritis, Sjögren's syndrome): Can affect corneal healing.

Uncontrolled diabetes: Risk of poor healing or infections.

Alternatives if you are not a candidate for LASIK/FEMTOLASIK

PRK (Photorefractive Keratectomy): Does not require a corneal flap (ideal for thin corneas).

SMILE: Minimally invasive flap-free technique (for myopia and astigmatism).

Intraocular lenses (ICL): For high prescriptions or inadequate corneas.

Cross-linking + PRK: In cases of mild keratoconus.