What Is Femto-LASIK? Procedure, Recovery, Benefits and Risks Explained

Worked for 1m 27s

Author: Dr Val Phua
Estimated reading time: 17 minutes

Femto-LASIK is a form of laser vision correction in which a femtosecond laser creates the corneal flap and an excimer laser reshapes the cornea to correct the prescription.

It is also commonly called:

Femtosecond LASIK
Femto-LASIK
All-laser LASIK
Bladeless LASIK

The term “bladeless” means that a mechanical microkeratome blade is not used to create the corneal flap. Femto-LASIK still involves a surgical procedure, a permanent flap interface and permanent removal of corneal tissue.

The two lasers perform different jobs:

The femtosecond laser creates a thin, hinged flap within the cornea.
The flap is lifted.
The excimer laser removes microscopic amounts of corneal tissue to correct myopia, hyperopia or astigmatism.
The flap is repositioned without stitches.

Current FDA documentation recognises that a LASIK flap may be created with either a mechanical microkeratome or a femtosecond laser. Modern Femto-LASIK allows the surgeon to programme flap dimensions such as thickness, diameter, hinge position and side-cut geometry with greater precision than traditional blade-based methods.

Femto-LASIK offers:

Rapid visual recovery
Relatively little early discomfort
Broad treatment flexibility
Customised excimer-laser options
A relatively straightforward enhancement pathway
More predictable flap construction than traditional microkeratome LASIK

However, it still carries risks including:

Dry eye
Glare and halos
Flap displacement or folds
Interface inflammation
Epithelial ingrowth
Residual prescription
Infection
Corneal ectasia
Rare loss of best-corrected vision

Femto-LASIK is not automatically the best procedure simply because it uses two lasers. The safest choice depends on the patient’s corneal structure, prescription, tear-film health, lifestyle and long-term visual priorities.

What Does “Femto” Mean?

“Femto” refers to the extremely short duration of each laser pulse.

One femtosecond is:

One quadrillionth of a second, or 10⁻¹⁵ seconds.

Femtosecond lasers deliver highly focused ultrashort pulses of near-infrared energy within the cornea.

At the precise focal point, the pulses create microscopic areas of tissue separation through a process known as photodisruption. Thousands of closely spaced laser spots are placed at a programmed depth, forming a smooth tissue plane from which the flap can be lifted.

Because the energy is focused within the transparent cornea, the femtosecond laser can create the flap without passing a blade across the corneal surface.

Is Femto-LASIK the Same as LASIK?

Femto-LASIK is a modern form of LASIK.

All LASIK procedures require:

A corneal flap
An excimer-laser treatment beneath the flap
Repositioning of the flap after treatment

The difference is how the flap is created.

Traditional Microkeratome LASIK

A mechanical device containing a blade moves across the cornea to create the flap.

Femto-LASIK

A femtosecond laser creates the flap using programmed laser pulses.

The excimer-laser part of the operation may be similar in both techniques.

Therefore, “Femto-LASIK” describes the method of flap creation, not the refractive treatment profile used beneath the flap.

Is Femto-LASIK the Same as Bladeless LASIK?

Yes. The terms are generally used interchangeably.

“Bladeless LASIK” means that the flap is made with a femtosecond laser rather than a bladed microkeratome.

However, bladeless does not mean:

No surgical instruments
No corneal incision
No flap
No removal of corneal tissue
No risk
A reversible procedure

The eyelids are still held open with a speculum, the flap is lifted using surgical instruments and the excimer laser permanently removes corneal tissue.

Is Femto-LASIK an All-Laser Procedure?

It is commonly described as all-laser LASIK because two lasers perform the principal refractive steps.

Femtosecond Laser

Creates the corneal flap.

Excimer Laser

Reshapes the underlying corneal tissue.

The term does not mean that every part of the operation is completed without instruments or physical contact.

How Does Femto-LASIK Correct Vision?

The cornea provides much of the eye’s focusing power.

Femto-LASIK changes the corneal curvature so that light focuses more accurately on the retina.

Myopia

In myopia, light focuses in front of the retina.

The excimer laser removes more tissue from the central cornea, flattening it and reducing its focusing power.

Hyperopia

In hyperopia, the optical system does not provide enough focusing power.

The laser applies treatment in a more peripheral ring pattern, making the central cornea relatively steeper.

Astigmatism

In astigmatism, the cornea or optical system has different focusing powers along different directions.

The excimer laser applies different amounts of correction along different meridians to produce a more balanced optical shape.

Current FDA labelling for one modern excimer platform includes myopia, hyperopia and mixed astigmatism within device-specific ranges. These ranges should not be interpreted as universal limits because suitability also depends on corneal anatomy and tissue calculations.

How Is Femto-LASIK Performed?

A typical procedure includes the following stages.

Preoperative Confirmation

Before treatment, the surgical team confirms:

Patient identity
Eye to be treated
Prescription
Treatment plan
Corneal measurements
Laser calibration
Intended optical zone

Anaesthetic eyedrops are applied, and the skin around the eye is cleaned.

Eyelid Speculum

A small instrument keeps the eyelids open.

The patient does not need to worry about blinking during treatment.

Femtosecond-Laser Docking

The eye is aligned beneath the femtosecond laser.

A curved or flat patient interface gently contacts the eye, and suction stabilises it.

During docking, the patient may feel:

Pressure
Tightness
Temporary dimming or loss of vision
A sensation that the eye is being held still

The pressure sensation lasts for a relatively short period.

Flap Creation

The femtosecond laser places microscopic pulses within the cornea to create:

The horizontal flap plane
The flap edge
A hinge that remains attached

The laser does not remove the flap. It creates a precise separation plane so that the surgeon can lift it.

Transfer to the Excimer Laser

Depending on the surgical platform, the patient may remain under an integrated system or be moved beneath a separate excimer laser.

Flap Lifting

The surgeon gently separates and lifts the flap, exposing the underlying corneal stroma.

Excimer-Laser Treatment

The patient looks towards a fixation light while the excimer laser reshapes the cornea.

Modern systems may incorporate:

Eye tracking
Pupil tracking
Iris registration
Cyclotorsion compensation
Wavefront-guided treatment
Topography-guided treatment
Wavefront-optimised profiles

Available features depend on the laser platform and treatment plan.

Flap Repositioning

The flap is returned to its original position.

The surgeon checks:

Flap alignment
Flap edge
Surface smoothness
Absence of debris or folds

The flap usually remains in place without stitches.

How Long Does Femto-LASIK Take?

The complete theatre process commonly takes several minutes per eye, although the actual laser delivery is much shorter.

Time is needed for:

Positioning
Suction and docking
Flap creation
Flap lifting
Excimer treatment
Flap replacement
Final examination

The exact duration varies with the equipment, prescription and surgical workflow.

Is Femto-LASIK Painful?

Anaesthetic eyedrops are used, so sharp pain should not normally occur during surgery.

Patients may feel:

Pressure during femtosecond docking
Tightness around the eye
Temporary vision dimming
Water around the eye
Mild awareness of movement
Bright or flashing lights

The pressure experienced during flap creation is usually brief.

After surgery, patients may experience:

Burning
Watering
Grittiness
Light sensitivity
Hazy vision
A desire to rub the eyes

These symptoms are usually most noticeable during the first several hours.

Severe or increasing pain is not considered normal and requires prompt review.

How Quickly Does Vision Recover?

Femto-LASIK generally offers one of the fastest recoveries among laser vision correction procedures.

The First Several Hours

Vision is often:

Hazy
Misty
Fluctuating
Sensitive to bright light

Patients are usually advised to rest with their eyes closed.

The Following Day

Many patients have functional unaided vision and can manage routine indoor activities.

The surgeon checks:

Flap position
Corneal clarity
Inflammation
Eye pressure
Ocular-surface healing
Visual acuity

The First Week

Vision commonly continues to sharpen.

Patients may still notice:

Dryness
Glare
Halos
Fluctuation
A difference between the two eyes

The First One to Three Months

Fine visual quality, tear-film stability and night vision generally continue to improve.

The final refractive result should not be judged solely from the first few days.

When Can You Return to Work?

Many patients can return to office-based work within one to three days.

More time may be needed when work involves:

Dust
Smoke
Chemicals
Strong airflow
Prolonged screen use
Night driving
Heavy physical activity
Risk of facial or eye injury

Frequent breaks and lubricating eyedrops may be needed when returning to screen work.

When Can You Drive?

Driving should resume only when:

Vision meets legal requirements
The patient feels visually comfortable
Glare and fluctuation are manageable
The postoperative examination is satisfactory
The surgeon has confirmed that driving is safe

Good daytime eye-chart vision does not necessarily mean that night driving is immediately comfortable.

What Are the Main Benefits of Femto-LASIK?

More Predictable Flap Thickness

A femtosecond laser creates the flap according to programmed dimensions.

Compared with mechanical microkeratomes, femtosecond systems generally provide:

More predictable thickness
Greater uniformity
More consistent flap diameter
More controllable hinge position
More adjustable side-cut geometry

An American Academy of Ophthalmology technology assessment concluded that femtosecond lasers are effective for LASIK flap creation and provide reliable visual outcomes. Comparative evidence has generally shown better flap-thickness predictability, although final visual acuity and refractive results may remain similar to microkeratome LASIK.

Reduced Risk of Certain Blade-Related Complications

Femtosecond flap creation avoids some microkeratome-related problems such as:

Irregular blade passage
Incomplete mechanical cuts
Free caps
Buttonhole flaps caused by blade mechanics
Certain extreme flap-thickness variations

Femto-LASIK introduces its own laser-specific complications, so the replacement of a blade does not eliminate flap risk.

Customisable Flap Design

The surgeon can usually programme:

Flap thickness
Flap diameter
Hinge width
Hinge position
Side-cut angle
Flap shape

This allows the flap plan to be adapted to:

Corneal diameter
Pupil size
Treatment zone
Corneal thickness
Surgeon preference
Expected enhancement strategy

Fast Visual Recovery

Because most of the surface epithelium remains intact, visual recovery is usually faster and early discomfort is generally less than after PRK or TransPRK.

Broad Refractive Treatment Options

The excimer-laser step may treat:

Myopia
Hyperopia
Regular astigmatism
Mixed astigmatism
Monovision targets

The available range varies with the platform, regulatory approval and individual corneal measurements.

Customised Excimer-Laser Treatment

Femto-LASIK may be combined with:

Wavefront-guided treatment
Topography-guided treatment
Wavefront-optimised treatment
Aspheric treatment profiles
Iris registration
Cyclotorsion compensation

These options may be useful when addressing specific optical or corneal characteristics.

Relatively Straightforward Enhancement

When a residual prescription remains, the original flap may sometimes be lifted and further excimer treatment performed.

Other options include:

PRK over the previous flap
Spectacles
Contact lenses
Observation

Flap lifting is not automatically appropriate, particularly many years later, because the risk of epithelial ingrowth may increase.

Is Femto-LASIK Better Than Traditional Blade LASIK?

Femto-LASIK has largely replaced microkeratome LASIK in many modern refractive practices because it provides more controllable flap geometry.

However, comparative evidence does not show that every final visual outcome is dramatically better.

Systematic reviews have generally found:

Similar final unaided visual acuity
Similar corrected visual acuity
Similar refractive accuracy
Better flap-thickness predictability with femtosecond lasers
Possible reductions in some induced optical aberrations
Different complication profiles

A Cochrane review and earlier meta-analyses concluded that femtosecond and mechanical flap creation both produced effective LASIK outcomes, although the certainty of evidence for some comparisons was limited.

The practical advantages of Femto-LASIK are mainly:

Greater flap planning control
Reduced dependence on blade mechanics
More predictable flap dimensions
Potentially fewer selected flap complications

It should not be marketed as risk-free or as providing perfect vision merely because the flap is laser-created.

Does Femto-LASIK Cause Dry Eye?

Yes. Dry eye is one of the most common concerns after LASIK.

Creating the flap cuts across corneal nerves involved in:

Corneal sensation
Tear secretion
Blinking
Ocular-surface regulation

The excimer-laser treatment also affects stromal nerves.

During recovery, patients may experience:

Burning
Grittiness
Watering
Fluctuating vision
Light sensitivity
Contact lens intolerance
Difficulty with prolonged screen use

A prospective study of patient-reported outcomes found that dry-eye symptoms generally improved over six months after myopic Femto-LASIK, although objective tear-film measurements did not always correlate with symptom improvement.

Is Dry Eye Always Temporary?

No.

For many patients, dryness improves substantially over weeks or months.

A smaller group may have prolonged symptoms, particularly when there was pre-existing:

Meibomian gland dysfunction
Aqueous tear deficiency
Blepharitis
Allergy
Contact lens intolerance
Reduced corneal sensation
High screen exposure
Autoimmune-related ocular-surface disease

Dry-eye risk should be assessed and treated before surgery.

Does a Thinner Flap Reduce Dry Eye?

A thinner flap may preserve more deeper corneal tissue and may reduce the number of stromal nerves transected.

Some studies have reported better corneal-sensation or tear-film recovery with thinner flaps, although flap thickness is not the only determinant of postoperative dryness. Flap diameter, hinge position, ablation depth and pre-existing ocular-surface health also matter.

Creating the thinnest technically possible flap is not automatically best. The flap must remain:

Structurally intact
Easy to lift
Free from folds
Appropriate for the treatment plan

Is Femto-LASIK Better Than SMILE for Dry Eye?

SMILE generally causes less early disruption of the anterior corneal nerve network because it avoids a broad hinged flap.

Comparative reviews generally report:

Less early dry-eye disturbance after SMILE
Faster corneal-sensation recovery after SMILE
Similar final visual acuity
Faster initial visual recovery after Femto-LASIK

The difference in dryness may become smaller over time, and SMILE can still cause dry eye.

What Is the LASIK Flap?

The flap is a thin layer of anterior corneal tissue that remains attached by a hinge.

It contains:

Epithelium
Bowman’s layer
Anterior stromal tissue
Corneal nerves

After excimer treatment, the flap is replaced over the underlying cornea.

The surface seals relatively quickly, but the deeper stromal interface remains a permanent anatomical plane.

Does the LASIK Flap Heal Completely?

The flap becomes stable enough for ordinary life, but it does not return to the structure of an untouched cornea.

Healing is strongest around the flap edge. The central interface remains relatively weak compared with unoperated corneal tissue.

This explains why:

The flap may be lifted for an enhancement
Severe trauma can occasionally move it years later
Flap-specific complications remain possible long term

Patients should not assume that “healed” means the flap has disappeared.

Can the Flap Move Years Later?

Severe direct trauma can occasionally displace or wrinkle a LASIK flap years after surgery.

The risk is low during ordinary daily activities but more relevant for:

Boxing
Martial arts
Rugby
Water polo
Wrestling
Military training
Police or tactical work
Occupations involving repeated facial trauma

SMILE or PRK may be preferred when avoiding a permanent flap is a major priority.

What Are the Risks of Femto-LASIK?

Femto-LASIK is generally safe in appropriately selected patients, but no elective corneal surgery is risk-free.

Under-correction, Overcorrection or Residual Astigmatism

The final prescription may not be exactly zero.

Possible reasons include:

Biological healing
Measurement variation
High original prescription
Treatment decentration
Cyclotorsion
Tear-film instability
Ongoing myopia progression

Management may include:

Observation
Spectacles
Contact lenses
Enhancement

Refractive Regression

Some of the corrected myopia or hyperopia may return over time.

Risk may be greater with:

High initial correction
Younger age
Continuing axial eye growth
Hyperopic treatment
Corneal remodelling
Natural-lens changes

A long-term result that changes does not necessarily mean that the laser treatment has “worn off.” The eye itself may have continued to change.

Dry Eye

Dryness may affect comfort and visual quality.

It can range from mild temporary symptoms to persistent ocular-surface disease or, rarely, neuropathic corneal pain.

Glare, Halos and Starbursts

Patients may notice:

Halos around headlights
Starbursts
Glare
Ghost images
Reduced contrast
Difficulty driving at night

Risk is influenced by:

Pupil size
Optical-zone size
Degree of correction
Treatment centration
Residual astigmatism
Tear-film instability
Higher-order aberrations

Flap Folds or Striae

Fine folds may form when the flap is not lying completely smoothly.

Minor folds may cause no visual problem.

Significant central folds can cause:

Blurred vision
Irregular astigmatism
Ghosting
Reduced corrected vision

Treatment may require lifting, smoothing or repositioning the flap.

Flap Displacement

The flap can shift if the eye is rubbed or traumatised during early healing.

Patients should avoid:

Eye rubbing
Forceful eyelid squeezing
Direct pressure on the eye
Contact sports until cleared
Accidental contact from children or pets

Epithelial Ingrowth

Surface epithelial cells may grow beneath the flap edge.

Small areas may remain stable and require observation.

Progressive epithelial ingrowth can cause:

Irregular astigmatism
Flap melting
Visual disturbance
Inflammation

Treatment may require lifting the flap and removing the epithelial cells.

Epithelial ingrowth appears to occur less often after primary femtosecond flap creation than after some microkeratome procedures, but the risk increases after flap relifting or enhancement.

Diffuse Lamellar Keratitis

Diffuse lamellar keratitis, or DLK, is sterile inflammation within the flap interface.

It may appear as fine inflammatory cells beneath the flap.

Symptoms may include:

Hazy vision
Light sensitivity
Discomfort
Reduced visual quality

Mild DLK may respond to intensive steroid treatment.

More severe disease may require lifting and irrigating the flap.

Prompt diagnosis is important because untreated severe DLK can cause tissue damage and loss of vision.

Interface Infection

Infection beneath a LASIK flap is rare but potentially sight-threatening.

Warning symptoms include:

Increasing pain
Worsening redness
Rapidly declining vision
Discharge
Marked light sensitivity
A visible white corneal spot

Urgent assessment and intensive antimicrobial treatment are required.

Incomplete Flap or Suction Loss

The femtosecond laser requires stable docking and suction.

If suction is lost, the flap may be:

Incomplete
Irregular
Unable to be safely lifted

Depending on the stage of treatment, the surgeon may:

Re-dock the eye
Adjust the laser plan
Postpone the operation
Convert to another procedure

Opaque Bubble Layer

The femtosecond laser creates microscopic gas bubbles while separating corneal tissue.

An opaque bubble layer may temporarily form if gas accumulates within the cornea.

It can:

Obscure certain landmarks
Interfere with eye tracking
Make flap lifting more difficult
Temporarily affect visualisation

It usually resolves without long-term harm.

Vertical Gas Breakthrough

Rarely, gas generated during flap creation may escape vertically towards the corneal surface.

This can interfere with flap formation and may be more likely when there is:

Corneal scarring
Previous surgery
A break in Bowman’s layer
Unusual corneal anatomy

Transient Light Sensitivity Syndrome

Some patients develop significant light sensitivity days or weeks after femtosecond flap creation despite relatively little visible inflammation.

This is known as transient light sensitivity syndrome.

It generally responds to topical steroids and usually resolves, but it remains a recognised femtosecond-laser-specific complication.

Rainbow Glare

Rainbow glare is a rare visual effect in which patients see coloured bands around bright lights.

It is believed to arise from diffraction caused by the regular pattern of femtosecond laser spots on the back surface of the flap.

Symptoms often improve with time, but persistent cases have been reported.

Interface Fluid Syndrome

Markedly raised eye pressure can cause fluid to collect beneath the flap.

This may mimic interface inflammation and may produce falsely low pressure readings when pressure is measured over the central fluid pocket.

Prompt recognition is important because treatment requires lowering the eye pressure rather than simply increasing steroids.

Corneal Ectasia

Corneal ectasia is progressive weakening and bulging of the cornea.

It may cause:

Increasing myopia
Irregular astigmatism
Ghosting
Reduced corrected vision
Need for rigid or scleral lenses
Need for corneal cross-linking
Rarely, corneal transplantation

The flap and excimer ablation both affect the corneal structure.

Risk is reduced by careful assessment of:

Corneal topography
Corneal tomography
Corneal thickness
Epithelial thickness
Residual stromal tissue
Percentage of tissue altered
Age
Prescription
Keratoconus susceptibility

Femto-LASIK should not be performed simply because a thin, predictable flap can be created. The underlying cornea must still be structurally suitable.

Can Femto-LASIK Cause Blindness?

Severe permanent visual loss is rare but possible.

Potential causes include:

Severe infection
Advanced corneal ectasia
Severe interface inflammation
Corneal scarring
Irregular astigmatism
Other uncommon complications

Most complications can be treated more effectively when recognised early.

Who May Be Suitable for Femto-LASIK?

A typical suitable candidate has:

An adult, stable prescription
Myopia, hyperopia or regular astigmatism within the treatment range
Healthy corneal topography and tomography
Adequate corneal thickness
Safe residual stromal tissue after flap and ablation
A stable ocular surface
No active infection or inflammation
No significant cataract
Realistic expectations
Willingness to attend follow-up
A lifestyle compatible with a permanent flap

Under one current FDA-approved excimer-laser indication, patients must be at least 18 years old and have a refractive change no greater than approximately 0.50 D during the preceding year. Exact criteria vary by platform and jurisdiction.

Who May Not Be Suitable?

Femto-LASIK may be unsuitable when there is:

Keratoconus
Pellucid marginal degeneration
Suspicious or progressive corneal tomography
Insufficient corneal tissue
Unstable refraction
Severe dry eye
Active eye infection or inflammation
Significant corneal scarring
Active autoimmune disease affecting healing
Poorly controlled diabetes
Pregnancy or breastfeeding
Significant cataract
Uncontrolled or advanced glaucoma
Vision-limiting retinal or optic nerve disease
Unrealistic expectations

A patient who is unsuitable for blade-based LASIK is not automatically made suitable merely by using a femtosecond laser.

Is Femto-LASIK Suitable for Thin Corneas?

Possibly, but the femtosecond laser does not make an unsafe cornea safe.

A predictable thin flap may preserve more residual stromal tissue than an unexpectedly thick mechanical flap.

However, the surgeon must still consider:

Total corneal thickness
Corneal shape
Posterior corneal elevation
Pachymetry distribution
Flap thickness
Laser-ablation depth
Optical-zone diameter
Residual stromal-bed thickness
Percentage of tissue altered
Epithelial mapping
Biomechanical risk

PRK, TransPRK, SMILE or ICL may provide a safer option depending on the findings.

Is Femto-LASIK Suitable for High Myopia?

Sometimes.

Higher corrections require more excimer-laser tissue removal.

This may increase:

Ectasia concern
Regression
Glare and halos
Induced optical aberrations
Enhancement limitations

A patient with high myopia and a thick, regular cornea may be suitable.

Another patient with a lower prescription may be unsuitable because of abnormal tomography or inadequate tissue.

ICL should be considered when corneal laser treatment would remove excessive tissue.

Is Femto-LASIK Suitable for Dry Eyes?

Mild or moderate dry eye may sometimes be treated before surgery.

The ocular surface should be stable before final:

Refraction
Corneal topography
Corneal tomography
Wavefront measurements

Severe or persistent dry-eye disease may rule out Femto-LASIK.

Treatment may include:

Preservative-free lubricants
Warm compresses
Eyelid hygiene
Meibomian gland treatment
Allergy treatment
Anti-inflammatory therapy
Temporary discontinuation of contact lenses

Is Femto-LASIK Suitable for Contact Sports?

Possibly, but flap trauma must be considered.

Patients involved in repeated direct-impact activities may prefer:

SMILE
PRK
TransPRK

because these procedures do not create a hinged LASIK flap.

The decision should account for the type, intensity and lifetime duration of the sport.

What Tests Are Needed Before Femto-LASIK?

Refraction and Visual Acuity

The examination measures:

Myopia or hyperopia
Astigmatism
Best-corrected visual acuity
Prescription stability

Cycloplegic Refraction

Dilating drops may be used to relax accommodation and confirm the true prescription.

Corneal Topography

Topography measures the curvature of the front corneal surface and helps detect:

Corneal asymmetry
Irregular astigmatism
Keratoconus patterns
Contact lens warpage

Corneal Tomography

Tomography evaluates:

Anterior corneal elevation
Posterior corneal elevation
Thickness distribution
Pachymetry progression
The thinnest corneal point
Ectasia susceptibility

Corneal Thickness and Tissue Calculations

The surgeon estimates:

Intended flap thickness
Ablation depth
Optical-zone requirements
Residual stromal-bed thickness
Percentage of tissue altered
Remaining structural reserve

Epithelial Thickness Mapping

Epithelial mapping may reveal:

Early keratoconus compensation
Contact lens-related distortion
Localised stromal irregularity
Previous surgical changes

Corneal Biomechanical Assessment

Biomechanical measurements may add information about corneal deformation.

No biomechanical test can guarantee that ectasia will not occur.

Dry-Eye and Eyelid Assessment

The surgeon evaluates:

Tear-film stability
Corneal staining
Meibomian glands
Blepharitis
Allergy
Tear production
Eyelid closure

Pupil Measurement

Pupil size helps with counselling about:

Night vision
Halos
Glare
Optical-zone planning

Eye Pressure and Optic Nerve

Baseline pressure and optic nerve findings should be documented.

LASIK changes corneal thickness and biomechanics, which can make future pressure measurements read artificially lower.

Natural-Lens Examination

The surgeon checks for:

Cataract
Early lens changes
Lens-related prescription shifts
Other causes of glare

Dilated Retinal Examination

This is particularly important for moderate and high myopia.

Femto-LASIK corrects the cornea but does not remove the underlying retinal risks associated with an elongated myopic eye.

Why Must Contact Lenses Be Stopped Before Testing?

Contact lenses can temporarily change:

Corneal curvature
Astigmatism
Tear-film stability
Epithelial thickness
Refraction
Corneal maps

The required contact lens-free period depends on:

Soft or rigid lenses
Toric lenses
Overnight wear
Duration of contact lens use
Evidence of corneal warpage

Final surgery should not be planned until repeated measurements are stable.

Femto-LASIK vs SMILE

Femto-LASIK

Creates a hinged flap
Uses femtosecond and excimer lasers
Provides very rapid visual recovery
Can treat myopia, hyperopia and selected astigmatism
Offers wavefront- and topography-guided options
Generally has a more straightforward enhancement pathway
Causes more early corneal nerve disruption

SMILE

Does not create a hinged flap
Uses a femtosecond laser to create a lenticule
Mainly treats myopia and myopic astigmatism
May cause less early dry eye
May suit contact-sport patients
Has more complex enhancement options

Comparative evidence generally shows similarly good final visual and refractive outcomes, with faster early recovery after Femto-LASIK and less early dryness after SMILE.

Femto-LASIK vs PRK or TransPRK

Femto-LASIK

Creates a flap
Faster recovery
Less postoperative pain
Lower surface-haze risk
More flap-related complications
More early nerve disruption

PRK or TransPRK

No flap
Epithelium must regrow
More pain
Slower visual recovery
Corneal haze risk
Preserves more load-bearing stromal tissue
May be preferred when trauma is a concern

Is Femto-LASIK Permanent?

Yes.

The excimer laser permanently removes corneal tissue.

The flap can be lifted, but the tissue removed beneath it cannot be restored.

Vision can nevertheless change later because of:

Continuing myopia progression
Corneal remodelling
Presbyopia
Cataract
Hormonal changes
Diabetes-related refractive shifts
Other eye disease

Does Femto-LASIK Prevent Presbyopia?

No.

Presbyopia occurs because the natural crystalline lens loses flexibility with age.

Femto-LASIK reshapes the cornea but does not restore natural accommodation.

Patients corrected fully for distance will generally need reading glasses as presbyopia develops.

A monovision strategy may be considered:

One eye is corrected for distance
The other retains mild myopia for near or intermediate vision

A contact lens trial is advisable before permanent monovision treatment.

Does Femto-LASIK Prevent Cataract?

No.

The natural lens remains inside the eye and continues to age.

When cataract develops, cataract surgery remains possible, but previous laser vision correction must be considered when calculating the cataract intraocular-lens power.

Patients should retain their refractive surgery records where possible.

How Long Do Femto-LASIK Results Last?

The corneal tissue removal is permanent.

Long-term LASIK studies extending beyond ten years generally show good safety and continued visual benefit in appropriately selected patients, although refractive regression and enhancement become more common with higher corrections and longer follow-up. Much of the longest-term evidence includes older platforms and does not exclusively represent current Femto-LASIK technology.

The result may change because:

The eye continues to elongate
The cornea remodels
Presbyopia develops
Cataract alters the prescription
Other eye disease develops

Frequently Asked Questions About Femto-LASIK

Is Femto-LASIK the Same as Bladeless LASIK?

Yes. The flap is created with a femtosecond laser rather than a mechanical blade.

Does Femto-LASIK Use Two Lasers?

Usually, yes.

The femtosecond laser creates the flap, and the excimer laser corrects the prescription.

Does the Femtosecond Laser Correct the Prescription?

Not during standard Femto-LASIK.

Its main role is to create the corneal flap.

The excimer laser performs the refractive reshaping.

Is Femto-LASIK Better Than Traditional LASIK?

It provides more predictable and customisable flap construction.

Final visual acuity and refractive accuracy may be similar when both procedures are uncomplicated.

Is Femto-LASIK Pain-Free?

Sharp pain should not occur during surgery because anaesthetic drops are used.

Pressure occurs during docking, and burning or watering may occur for several hours afterwards.

How Fast Is Recovery?

Many patients have functional vision by the following day.

Dryness, glare and visual fluctuation may continue for weeks.

Can Femto-LASIK Treat Astigmatism?

Yes, regular astigmatism can be treated within the platform’s suitable range.

Can Femto-LASIK Treat Hyperopia?

Yes, compatible excimer-laser platforms can treat selected hyperopia and hyperopic astigmatism.

Is Femto-LASIK Suitable for High Myopia?

Possibly, when enough healthy corneal tissue remains.

ICL may be safer if the laser treatment would remove excessive tissue.

Is Femto-LASIK Suitable for Thin Corneas?

Possibly, but a predictable thin flap does not make every thin cornea suitable.

PRK, SMILE or ICL may provide a better structural safety margin.

Does Femto-LASIK Cause Dry Eye?

Temporary dryness is common.

Persistent symptoms can occur, especially when dry-eye or eyelid-gland disease was present before surgery.

Can the Flap Move?

It can move during early healing if the eye is rubbed or injured.

Severe trauma can rarely disturb it years later.

Can I Rub My Eyes After Femto-LASIK?

Eye rubbing should be avoided during early recovery.

Habitual vigorous rubbing should also be discouraged long term.

Does the Flap Disappear?

No.

The flap remains as a permanent corneal interface.

Can Femto-LASIK Be Reversed?

No.

The laser-removed stromal tissue cannot be replaced.

Can Femto-LASIK Cause Ectasia?

Yes, although the risk is low after appropriate screening.

Abnormal corneal structure or excessive tissue removal increases concern.

Can Femto-LASIK Cause Halos?

Yes.

Halos, glare and starbursts may occur, particularly during early recovery or in dim lighting.

Can I Still Need Glasses?

Yes.

Glasses may still be needed for:

Residual prescription
Night driving
Fine visual tasks
Reading after presbyopia
Future refractive change

Can Femto-LASIK Be Enhanced?

Possibly.

The flap may sometimes be relifted, or a surface-laser enhancement may be performed.

Suitability depends on corneal thickness, maps and prescription stability.

Is Femto-LASIK Suitable for Contact Sports?

It can be, but the permanent flap must be considered.

SMILE or surface ablation may be preferred when repeated direct eye trauma is likely.

Can Femto-LASIK Cause Blindness?

Severe permanent visual loss is rare but possible following serious infection, ectasia, scarring or another major complication.

Do I Still Need Eye Examinations?

Yes.

Regular examinations remain important for:

Dry eye
Eye pressure
Glaucoma
Cataract
Corneal health
Retinal health
Myopia-related complications

Key Takeaway

Femto-LASIK is a modern form of LASIK in which:

A femtosecond laser creates a thin corneal flap.
The flap is lifted.
An excimer laser reshapes the underlying cornea.
The flap is repositioned without stitches.

Its potential advantages include:

Predictable flap thickness and geometry
No mechanical blade for flap creation
Rapid visual recovery
Relatively little early discomfort
Broad treatment flexibility
Wavefront- and topography-guided options
A relatively straightforward enhancement pathway

Its limitations include:

A permanent corneal flap
Early dry-eye disturbance
Flap displacement or folds
Interface inflammation
Epithelial ingrowth
Glare and halos
Corneal ectasia risk
Permanent removal of corneal tissue

Femto-LASIK is generally suitable only when the patient has:

A stable prescription
Healthy corneal topography and tomography
Adequate corneal tissue
A controlled ocular surface
No significant cataract or uncontrolled eye disease
Realistic expectations

The use of a femtosecond laser improves flap control but does not make an unsuitable cornea safe for LASIK.

For some patients, SMILE, PRK, TransPRK or ICL may provide a better safety profile.

The safest procedure is determined by the complete examination—not by whether the clinic uses the newest laser or describes the treatment as “bladeless.”

References

US Food and Drug Administration. ZEISS MEL 90 LASIK Patient Information Booklet. Updated 2024.
US Food and Drug Administration. What Should I Expect Before, During and After LASIK Surgery?
Farjo AA, Sugar A, Schallhorn SC, et al. Femtosecond Lasers for LASIK Flap Creation: A Report by the American Academy of Ophthalmology. 2013. PMID: 23174396.
Dos Santos AM, Torricelli AAM, Marino GK, et al. Femtosecond Laser-Assisted LASIK Flap Complications. 2016. PMID: 26812715.
Sahay P, Bafna RK, Reddy JC, Vajpayee RB, Sharma N. Complications of Laser-Assisted In Situ Keratomileusis. 2021. PMID: 34146007.
Kahuam-López N, Navas A, Castillo-Salgado C, et al. Mechanical Microkeratome Versus Femtosecond Laser in LASIK for Myopia. Cochrane review, 2020. PMID: 32255519.
Zhang ZH, Jin HY, Suo Y, et al. Femtosecond Laser Versus Mechanical Microkeratome for LASIK: A Meta-analysis. 2011. PMID: 22108110.
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Yan MK, Chang JS, Chan TC. Refractive Regression After LASIK. 2018. PMID: 29700964.
Alió JL, Muftuoglu O, Ortiz D, et al. Ten-Year Follow-up of LASIK for Myopia. 2008. PMID: 18154754.
Ikeda T, Shimizu K, Igarashi A, et al. Twelve-Year Follow-up of LASIK for Moderate to High Myopia. 2017.
Castro-Luna G, Jiménez-Rodríguez D, Alió JL. Long-Term Safety and Effectiveness of LASIK and PRK for Myopia. 2020. PMID: 33255392.