Femto-LASIK: Suitability, Procedure, Risks and Recovery

Author: Dr Val Phua
Estimated reading time: 22 minutes

Femto-LASIK is a laser vision-correction procedure used to reduce dependence on spectacles or contact lenses.

It is also known as:

Femtosecond LASIK
Femtosecond laser-assisted LASIK
Bladeless LASIK
All-laser LASIK

During Femto-LASIK, two different lasers perform separate parts of the procedure:

A femtosecond laser creates a thin corneal flap.
An excimer laser reshapes the underlying corneal tissue.

The flap is then repositioned without stitches.

By changing the curvature of the cornea, Femto-LASIK alters how light is focused onto the retina.

It may correct selected patients with:

Myopia, or short-sightedness
Hyperopia, or long-sightedness
Regular astigmatism
Presbyopia through a monovision strategy in suitable patients

Femto-LASIK differs from older mechanical-microkeratome LASIK because the flap is created with a laser rather than a moving blade.

The femtosecond laser provides greater control over:

Flap thickness
Flap diameter
Flap position
Hinge location
Side-cut angle
Flap architecture

Studies comparing femtosecond and mechanical flap creation generally show more predictable and uniform flap thickness with femtosecond lasers. However, the final visual efficacy and safety of well-performed femtosecond and mechanical LASIK have often been broadly comparable in clinical trials.

Femto-LASIK commonly provides rapid visual recovery and excellent refractive outcomes in appropriately selected patients. Ten-year follow-up data also support the long-term effectiveness and safety of femtosecond LASIK for myopia, although the eye may continue to change with ageing or myopic progression.

However, Femto-LASIK is still an operation on healthy corneal tissue.

Possible side effects and complications include:

Dry eye
Glare, halos and starbursts
Residual refractive error
Regression
Flap folds
Flap displacement
Diffuse lamellar keratitis
Epithelial ingrowth
Infection
Corneal ectasia
Persistent ocular discomfort
Rare loss of corrected vision

Careful patient selection is therefore more important than simply choosing the newest laser platform.

The Quick Answer

What Is Femto-LASIK?

Femto-LASIK is LASIK in which the corneal flap is created with a femtosecond laser.

After the flap is lifted, an excimer laser reshapes the exposed corneal stroma.

The flap is repositioned and adheres naturally.

Why Is It Called “Bladeless LASIK”?

Traditional LASIK used a mechanical microkeratome containing an oscillating blade to create the flap.

Femto-LASIK uses focused laser pulses instead.

The term “bladeless” refers specifically to flap creation.

The surgeon still uses fine instruments to:

Lift the flap
Inspect the interface
Reposition the flap
Remove debris or fluid when necessary

Is Femto-LASIK the Same as LASIK?

Femto-LASIK is a type of LASIK.

All Femto-LASIK is LASIK, but not every historical LASIK procedure used a femtosecond laser.

Modern LASIK is frequently performed with femtosecond flap creation.

Is Femto-LASIK Better Than Ordinary LASIK?

Femto-LASIK provides:

Greater flap-thickness predictability
More uniform flap architecture
Programmable side cuts
Greater flexibility in flap diameter and hinge position
No risk of blade-related mechanical malfunction

However, meta-analyses have not consistently shown major differences in final unaided vision, safety or refractive accuracy compared with well-performed microkeratome LASIK. Femtosecond LASIK may produce fewer total and spherical higher-order aberrations and more predictable flaps, while diffuse lamellar keratitis has been reported more often with some femtosecond systems.

What Does Femto-LASIK Treat?

Femto-LASIK may treat:

Myopia
Hyperopia
Regular astigmatism
Selected residual refractive errors
Presbyopia through monovision

The treatable range depends on:

Corneal shape
Corneal thickness
Prescription
Planned flap thickness
Required ablation depth
Optical-zone size
Residual stromal-bed calculations
Laser platform
Local regulatory approval
Surgeon assessment

Is Femto-LASIK Painful?

Most patients feel little or no pain during surgery.

Anaesthetic eye drops numb the surface.

The patient may notice:

Pressure around the eye
Temporary dimming or greying of vision
A bright fixation light
Clicking sounds
Mild pulling or movement
The smell produced during excimer-laser ablation

The smell does not mean that the eye is burning.

How Long Does It Take?

Femto-LASIK commonly takes approximately 10 to 20 minutes for both eyes.

The individual laser treatments may each take only seconds.

Additional time is required for:

Positioning
Suction
Flap creation
Flap lifting
Excimer-laser alignment
Flap replacement
Final inspection

How Quickly Does Vision Recover?

Many patients have useful vision by the following day.

Vision commonly continues to improve over:

Several days
Several weeks
Occasionally several months

Recovery may be affected by:

Dry eye
Prescription
Astigmatism
Corneal healing
Treatment profile
Night-time pupil size
Visual demands

Is Femto-LASIK Permanent?

The corneal tissue removed by the excimer laser does not regrow in its original form.

However, vision may change later because of:

Continuing myopic progression
Refractive regression
Presbyopia
Cataract development
Diabetes-related fluctuation
Corneal biomechanical change
Other ocular disease

A ten-year study of PRK and femtosecond LASIK found both procedures remained effective and safe over long-term follow-up, although unaided visual effectiveness was lower than the immediate postoperative peak in some eyes.

Will I Never Need Spectacles Again?

Not necessarily.

Spectacles may still be useful for:

Fine reading
Night driving
Small residual refractive errors
Very detailed distance tasks
Presbyopia
Future cataract-related changes
Progressive myopia

The aim is to reduce dependence on spectacles or contact lenses rather than guarantee that they will never be required again.

What Is a Femtosecond Laser?

A femtosecond is one quadrillionth of a second.

A femtosecond laser produces extremely short pulses of infrared laser energy.

The energy is focused at a precise depth within the cornea.

Each pulse produces:

A microscopic plasma
A tiny cavitation bubble
Separation of adjacent stromal tissue

Thousands of closely spaced pulses create a controlled tissue-separation plane.

This process is called photodisruption.

How Does the Femtosecond Laser Create a Flap?

The laser creates:

A horizontal stromal plane
A circumferential side cut
A small uncut hinge

The surgeon then opens the side cut and lifts the flap at the hinge.

Unlike many mechanical microkeratome flaps, femtosecond flaps can be programmed with a relatively planar thickness profile. Imaging studies show that modern femtosecond systems can produce reproducible flaps close to the intended thickness.

Why Does Flap Predictability Matter?

The surgeon plans the amount of untouched stromal tissue that should remain after:

Flap creation
Excimer-laser ablation

A flap that is thicker than expected leaves less residual stromal tissue.

More predictable flap thickness therefore improves the reliability of biomechanical planning.

Femtosecond systems also allow the surgeon to select:

Thinner flaps
Flap diameter
Side-cut angle
Hinge location
Hinge width
Energy and spot separation

A predictable thin flap may preserve more residual stromal bed than a thicker flap, although it does not eliminate ectasia risk.

What Is the Difference Between the Two Lasers?

Femtosecond Laser

The femtosecond laser creates the flap.

It separates corneal tissue at a chosen depth.

Excimer Laser

The excimer laser corrects the prescription.

It removes microscopic amounts of stromal tissue through photoablation.

It changes the curvature of the cornea without relying on thermal cutting.

Femto-LASIK is therefore not a single-laser procedure.

Understanding Refractive Error

Myopia

Myopia occurs when light focuses in front of the retina.

Patients usually see near objects more clearly than distant objects.

Myopic Femto-LASIK flattens the central cornea to reduce its focusing power.

Hyperopia

Hyperopia occurs when the eye has insufficient focusing power or is relatively short.

Hyperopic Femto-LASIK removes tissue in a surrounding pattern to steepen the central cornea.

Hyperopic treatments may be more affected by:

Treatment centration
Latent hyperopia
Age-related changes
Regression
Pupil size
Corneal healing

Astigmatism

Astigmatism occurs when the eye has different focusing power in different meridians.

The excimer laser applies an asymmetric treatment to reduce the cylindrical component.

Accurate astigmatism correction depends on:

Reliable refraction
Corneal regularity
Treatment-axis alignment
Cyclotorsion compensation
Eye tracking
Treatment centration
Healing

Presbyopia

Presbyopia is the age-related loss of the natural lens’s ability to focus at near.

Femto-LASIK reshapes the cornea but does not restore the flexibility of the natural lens.

A patient who receives excellent distance correction may still require reading spectacles as presbyopia progresses.

Monovision Femto-LASIK

Monovision is a strategy in which:

One eye is corrected primarily for distance.
The other eye is left mildly short-sighted for intermediate or near vision.

Possible benefits include:

Reduced dependence on reading spectacles
Useful intermediate vision
Avoidance of an intraocular multifocal lens

Possible disadvantages include:

Reduced stereoacuity
Reduced depth perception
Reduced binocular distance sharpness
Night-driving difficulty
Inability to adapt

A contact-lens monovision trial is often helpful before permanent treatment.

Who May Be Suitable for Femto-LASIK?

A suitable patient generally has:

A stable spectacle prescription
Healthy corneal shape
Adequate corneal thickness
No evidence of keratoconus
No corneal ectasia
A manageable refractive error
A healthy or treatable ocular surface
No visually significant cataract
No uncontrolled eye disease
Realistic expectations
The ability to cooperate during surgery

How Stable Must the Prescription Be?

The prescription should generally remain stable for at least approximately one year.

A small change does not always exclude treatment, but significant ongoing progression suggests that the result may not remain stable.

Refractive instability is more likely with:

Younger age
Progressive myopia
Pregnancy
Breastfeeding
Poorly controlled diabetes
Hormonal change
Developing cataract
Certain medications

Is There a Minimum Age?

Femto-LASIK is generally not performed below 18 years of age.

Reaching 18 does not automatically establish suitability.

Many young adults continue to experience progressive myopia.

Is There a Maximum Age?

There is no universal maximum age.

Older patients require assessment for:

Presbyopia
Early cataract
Dry eye
Glaucoma
Macular degeneration
Corneal endothelial health
Expectations regarding near vision

When early cataract or lens-related refractive change is present, cataract surgery may provide a more appropriate long-term solution.

Who May Not Be Suitable for Femto-LASIK?

Femto-LASIK may be inappropriate or require particular caution in patients with:

Keratoconus
Suspicious corneal tomography
Corneal ectasia
Inadequate corneal thickness
Unstable refraction
Severe dry eye
Active blepharitis
Recurrent corneal erosion
Epithelial basement membrane dystrophy
Active corneal infection
Previous herpetic keratitis
Uncontrolled glaucoma
Active uveitis
Visually significant cataract
Poorly controlled diabetes
Active autoimmune disease
Pregnancy or breastfeeding
Unrealistic expectations

Thin Corneas

A thinner cornea does not automatically exclude Femto-LASIK.

The surgeon considers:

Total corneal thickness
Corneal shape
Planned flap thickness
Ablation depth
Residual stromal bed
Percentage of tissue altered
Patient age
Degree of correction
Ectasia-risk indices

A thin but structurally normal cornea may sometimes be treated with a thin femtosecond flap.

However, PRK, SMILE or ICL may be more appropriate in some cases.

A thin cornea with suspicious tomography should not be treated merely because a thin flap can technically be created.

Pregnancy and Breastfeeding

Elective Femto-LASIK is generally postponed during pregnancy and breastfeeding.

Possible concerns include:

Refractive fluctuation
Corneal-curvature change
Tear-film instability
Medication exposure
Hormonal effects on healing

Measurements should be repeated after vision and the ocular surface have stabilised.

Diabetes

Well-controlled diabetes does not automatically exclude every patient.

Suitability depends on:

Blood-glucose stability
HbA1c
Refraction stability
Diabetic retinopathy
Corneal sensation
Dry eye
Wound healing
General medical health

Poorly controlled diabetes may cause:

Fluctuating refraction
Delayed healing
Infection risk
Less predictable results

Autoimmune Disease

Active or poorly controlled autoimmune disease may increase the risk of:

Severe dry eye
Delayed epithelial healing
Inflammation
Infection
Corneal ulceration
Corneal melting
Unpredictable outcomes

Stable systemic disease requires individual assessment and, where appropriate, coordination with the treating physician.

Contact Lenses Before Assessment

Contact lenses may temporarily alter:

Corneal shape
Refraction
Tear-film stability
Epithelial thickness

They should be discontinued before final measurements.

The required interval depends on:

Soft or rigid lens type
Duration of wear
Orthokeratology
Corneal warpage
Stability of repeat maps

Rigid gas-permeable and orthokeratology lenses may require a substantially longer period of discontinuation.

The Pre-Femto-LASIK Assessment

The assessment must answer:

Can the prescription be corrected accurately?
Is the cornea structurally safe for a flap and ablation?
Is Femto-LASIK preferable to PRK, SMILE or ICL?
Is the ocular surface healthy enough for reliable measurements?
Does the patient understand the possible trade-offs?

Medical and Eye History

Important information includes:

Previous eye surgery
Contact-lens use
Dry eye
Eye rubbing
Allergy
Recurrent corneal erosion
Eye trauma
Herpetic eye disease
Glaucoma
Retinal disease
Diabetes
Autoimmune disease
Pregnancy plans
Medication
Contact sports
Occupational requirements
Night-driving needs

Visual-Acuity Testing

Both unaided and corrected vision are measured.

Corrected vision helps establish the eye’s visual potential.

Femto-LASIK cannot correct reduced vision caused by:

Amblyopia
Retinal disease
Optic-nerve damage
Corneal scarring
Neurological disease

Manifest Refraction

The patient compares different lenses to establish the subjective spectacle prescription.

The test may be repeated because small inconsistencies can affect:

Refractive accuracy
Astigmatism treatment
Ablation depth
Binocular balance

Cycloplegic Refraction

Dilating drops temporarily relax the eye’s focusing mechanism.

This may be useful for:

Younger patients
Hyperopia
Accommodative spasm
Inconsistent refraction
Avoiding excessive myopic correction

Corneal Topography

Topography maps the curvature of the front corneal surface.

It helps identify:

Regular astigmatism
Irregular astigmatism
Contact-lens warpage
Decentration
Keratoconus-like patterns
Previous treatment zones

Corneal Tomography

Tomography assesses the three-dimensional corneal structure.

It may analyse:

Anterior elevation
Posterior elevation
Corneal thickness
Thickness distribution
Curvature
Corneal volume
Ectasia-risk indices

Normal corrected visual acuity does not exclude early keratoconus.

Tomographic screening is central to reducing the risk of postoperative ectasia.

Pachymetry

Pachymetry measures corneal thickness.

The surgeon considers:

Starting thickness
Intended flap thickness
Excimer ablation depth
Residual stromal bed
Percentage of tissue altered
Corneal shape
Optical-zone size
Patient age
Prescription

No single thickness number establishes safety by itself.

Epithelial Thickness Mapping

The epithelium may redistribute itself and partly hide an underlying stromal irregularity.

Epithelial mapping may help identify:

Early keratoconus
Contact-lens warpage
Epithelial compensation
Previous ablation patterns
Localised corneal irregularity

Corneal Biomechanical Assessment

Selected clinics use instruments that assess how the cornea deforms after an air pulse.

Biomechanical information may help assess ectasia susceptibility.

It should be interpreted together with:

Topography
Tomography
Pachymetry
Prescription
Age
Family history
Eye-rubbing history

Wavefront Aberrometry

Wavefront testing measures how light passes through the eye.

It may identify:

Defocus
Astigmatism
Coma
Spherical aberration
Other higher-order aberrations

The information may be used for a wavefront-guided treatment when measurements are sufficiently reliable.

Tear-Film and Dry-Eye Evaluation

The ocular surface should be assessed for:

Tear-film instability
Corneal staining
Conjunctival staining
Meibomian gland dysfunction
Blepharitis
Reduced tear production
Contact-lens-related inflammation

An unstable tear film can reduce the reliability of:

Refraction
Topography
Wavefront measurements
Treatment planning

Dry eye should be treated before surgery whenever possible.

Pupil and Centration Assessment

The surgeon may assess:

Pupil size
Pupil centre
Corneal vertex
Visual axis
Fixation
Angle kappa

These factors may influence:

Treatment centration
Optical-zone selection
Night vision
Glare
Halos
Coma

Eye-Pressure Measurement

Eye pressure is measured to screen for glaucoma.

After myopic Femto-LASIK, conventional pressure readings may appear artificially lower because the cornea has become thinner and flatter.

Future eye-care providers should be informed about the history of refractive surgery.

Dilated Retinal Examination

The retina and optic nerve may be examined for:

Retinal holes
Retinal tears
Lattice degeneration
Retinal detachment
Myopic macular disease
Glaucoma
Other causes of limited vision

Correcting myopia does not remove the retinal risks associated with a long, highly myopic eye.

How Is Femto-LASIK Performed?

Step 1: Confirming the Treatment

Before surgery, the team confirms:

Patient identity
Correct eye
Prescription
Astigmatism axis
Laser settings
Flap dimensions
Corneal measurements
Treatment profile

Step 2: Anaesthetic Drops

Anaesthetic drops numb the cornea.

The eyelids and surrounding skin are cleaned.

An eyelid holder keeps the eye open.

The patient does not need to worry about blinking.

Step 3: Positioning Under the Femtosecond Laser

The patient lies beneath the femtosecond-laser system.

A curved or flat contact interface approaches the eye, depending on the platform.

Step 4: Applying Suction

A suction ring stabilises the eye.

The patient may feel firm pressure.

Vision may:

Dim
Grey out
Become blurry
Temporarily disappear

This is expected during suction.

Step 5: Creating the Flap

The femtosecond laser delivers thousands of focused pulses within the corneal stroma.

The laser creates:

The flap bed
The flap edge
The hinge

The laser treatment commonly takes only several seconds.

Step 6: Releasing Suction

Suction is released after the laser sequence is complete.

Vision usually returns immediately but remains blurred.

Step 7: Opening and Lifting the Flap

The surgeon opens the flap edge with a fine instrument.

The flap is gently lifted at its hinge.

The underlying stromal bed is exposed.

Step 8: Aligning the Excimer Laser

The patient looks towards the excimer-laser fixation light.

The platform may use:

Eye tracking
Pupil recognition
Iris registration
Cyclotorsion compensation
Corneal-vertex alignment

The available functions depend on the system.

Step 9: Excimer-Laser Reshaping

The excimer laser removes microscopic amounts of stromal tissue according to the treatment plan.

The procedure may use:

Wavefront-optimised treatment
Wavefront-guided treatment
Topography-guided treatment
Aspheric treatment
Platform-specific customised planning

Step 10: Irrigating the Interface

The surgeon may irrigate the stromal bed and flap interface.

This helps remove:

Debris
Excess fluid
Loose epithelial cells
Inflammatory material

Step 11: Replacing the Flap

The flap is placed back into its original position.

The surgeon checks:

Centration
Edge alignment
Smoothness
Absence of folds
Interface cleanliness
Flap adherence

No stitches are usually required.

Step 12: Final Examination

The eye is examined at the microscope before the patient leaves the procedure room.

The surgeon confirms that the flap is:

Centred
Smooth
Securely positioned
Free from significant debris

Can Both Eyes Be Treated Together?

Yes.

Bilateral same-day Femto-LASIK is common.

Advantages include:

Simultaneous recovery
Reduced binocular imbalance
One principal recovery period
Fewer procedure visits

Each eye still requires separate planning and safety checks.

Flap Customisation

The femtosecond laser allows the surgeon to select several flap parameters.

Flap Thickness

A thinner flap may preserve more residual stromal tissue.

An excessively thin flap may be more delicate and technically difficult to handle.

Flap Diameter

The diameter must provide sufficient access for the excimer optical zone while remaining appropriate for the corneal anatomy.

Hinge Position

The hinge may be placed superiorly or nasally depending on:

Laser platform
Surgeon preference
Corneal anatomy

Side-Cut Angle

A steeper side cut may improve edge apposition and flap stability.

Modern femtosecond systems can create near-vertical flap edges, unlike the more sloping edges commonly produced by traditional microkeratomes.

Wavefront-Optimised Femto-LASIK

Wavefront-optimised treatment adjusts laser delivery towards the peripheral treatment zone to reduce the induction of spherical aberration.

It does not use a completely individualised map of every higher-order aberration.

Wavefront-Guided Femto-LASIK

Wavefront-guided treatment incorporates optical measurements from the entire eye.

It may be considered when:

Measurements are repeatable
Higher-order aberrations are clinically relevant
Registration is reliable
The platform supports the intended correction

Topography-Guided Femto-LASIK

Topography-guided treatment is based primarily on measured corneal shape.

It may aim to:

Regularise the corneal surface
Improve treatment centration
Correct refractive error
Reduce selected higher-order aberrations
Improve optical symmetry

Recent prospective studies report excellent visual and refractive results with topography-guided femtosecond LASIK in selected myopic patients. One study reported 20/20 or better unaided vision in the large majority of eyes at 12 months, while a more recent patient-reported study found high satisfaction and improved symptoms at three months. These results describe selected study populations and are not a guarantee for every patient.

Is One Treatment Profile Best?

No single profile is best for every eye.

The choice depends on:

Corneal shape
Wavefront quality
Prescription
Pupil characteristics
Previous surgery
Laser platform
Repeatability of measurements
Surgeon planning

Advanced customisation cannot compensate for an unsuitable cornea.

What Does the Patient Experience During Surgery?

The patient may notice:

Pressure during suction
Temporary dimming or loss of vision
Bright fixation lights
Clicking sounds
The fixation light becoming blurred
Fluid moving across the eye
The smell associated with excimer ablation

The patient should report sharp pain or unexpected discomfort.

What Happens if I Blink?

An eyelid holder prevents blinking during the important parts of the procedure.

What Happens if I Move My Eye?

The eye is stabilised during femtosecond flap creation.

During excimer treatment, modern tracking systems monitor small eye movements.

The laser may pause when alignment is lost.

The patient should still follow fixation instructions.

What Happens Immediately Afterwards?

Temporary symptoms may include:

Hazy vision
Watering
Burning
Grittiness
Light sensitivity
Halos
Difficulty keeping the eyes open

Discomfort is commonly most noticeable during the first several hours.

Eye Drops After Femto-LASIK

Medication may include:

Antibiotic drops
Steroid drops
Preservative-free lubricants
Other dry-eye treatment

Patients should:

Wash their hands
Avoid touching the bottle tip to the eye
Use drops according to schedule
Space different drops apart
Avoid stopping steroid drops without advice

The First Night

Protective eye shields may be recommended during sleep.

Patients should avoid:

Eye rubbing
Pressing on the eyelids
Sleeping face-down
Accidental contact from children or pets

The First Day

Many patients notice substantial visual improvement.

Temporary symptoms may include:

Misty vision
Glare
Halos
Fluctuation
Dryness
Light sensitivity

A postoperative examination checks:

Flap position
Flap edge
Interface
Corneal surface
Inflammation
Infection

The First Week

Vision generally continues to sharpen.

Fluctuation may be more noticeable:

Late in the day
During prolonged screen use
In air-conditioned environments
When the tear film is unstable
At night

The First Month

Dryness, glare and intermittent blur commonly continue to improve.

Small refractive changes may still occur.

Three to Six Months

The tear film, corneal nerves and optical system continue adapting.

Most routine refractive results are stable by this period, although higher prescriptions or significant dry eye may require longer.

When Can I Return to Work?

Many patients can return to desk work within several days.

A longer interval may be needed when the occupation involves:

Dust
Chemical exposure
Outdoor work
Heavy physical activity
Night driving
Risk of eye trauma
Very detailed visual tasks

Can I Use a Computer or Phone?

Yes.

Screens do not damage the flap or reverse the treatment.

However, screen use reduces blinking and may worsen:

Dryness
Burning
Fluctuating vision
Eye fatigue

When Can I Drive?

Driving should resume only when:

Vision meets the legal requirement
The patient feels comfortable
Depth perception is satisfactory
Glare is manageable
Sedative effects have resolved
The surgeon has not advised otherwise

The patient should not drive home immediately after surgery.

When Can I Exercise?

Gentle walking is usually possible early.

Strenuous exercise may be restricted temporarily.

Patients should avoid:

Sweat entering the eye
Eye rubbing
Dusty environments
Facial impact
Contact sports

When Can I Swim?

Swimming is generally avoided during the early healing period.

Pool, sea and spa water may contain:

Bacteria
Parasites
Irritating chemicals

When Can I Wear Eye Makeup?

Eye makeup should be avoided during early recovery.

Old mascara, eyeliner and applicators may be contaminated.

When Can I Fly?

Uncomplicated Femto-LASIK does not place gas inside the eye and usually does not prevent flying.

Aircraft cabins may worsen dry-eye symptoms.

Travel should not interfere with early postoperative reviews.

Expected Visual Results

Femto-LASIK generally produces excellent unaided distance vision in appropriately selected patients.

A prospective study reported that all included eyes achieved 20/20 unaided vision at 12 months, with all eyes within 0.50 dioptres of the intended target. Other modern studies report similarly high rates of 20/20 vision and refractive accuracy, although results vary with prescription, platform and patient selection.

A large Singapore clinical audit of 37,932 LASIK-treated eyes found that outcomes improved significantly over a decade as technology, nomograms and clinical governance evolved.

Is 20/20 the Same as Perfect Vision?

No.

A high-contrast letter chart does not fully measure:

Contrast sensitivity
Night vision
Glare
Halos
Starbursts
Ghost images
Tear-film fluctuation
Visual comfort
Quality of vision

A patient may read 20/20 and still experience visual symptoms.

Patient Satisfaction

Most appropriately selected LASIK patients report high satisfaction.

In the FDA-associated PROWL studies, dissatisfaction with surgery was reported by approximately 1% to 2% of participants. However, among patients who did not have a particular symptom before surgery, 43% to 46% reported at least one new visual symptom at three months, and approximately 28% of those with normal preoperative dry-eye scores reported some degree of dry-eye symptoms. Most symptoms did not prevent ordinary activities.

Patient satisfaction depends not only on spectacle independence but also on:

Unaided visual acuity
Residual astigmatism
Dry-eye symptoms
Night-time visual quality
Whether expectations were realistic

A comparative real-world study identified unaided vision, postoperative astigmatism and dry-eye symptoms as major determinants of satisfaction after Femto-LASIK and SMILE.

Dry Eye After Femto-LASIK

Dry eye is one of the most common postoperative concerns.

Femto-LASIK disrupts corneal nerves through:

Flap creation
Stromal ablation
Flap side cuts

These nerves contribute to:

Corneal sensation
Reflex tearing
Blinking
Tear-film regulation
Epithelial health

Possible symptoms include:

Burning
Grittiness
Fluctuating vision
Redness
Light sensitivity
Tired eyes
Excessive tearing
Difficulty wearing contact lenses

How Long Does Dry Eye Last?

For many patients, symptoms improve substantially within:

Several weeks
Three to six months
Occasionally up to one year

A minority develop persistent symptoms.

Meta-analysis confirms that LASIK temporarily affects tear-film and ocular-surface measures.

Risk Factors for Dry Eye

Possible risk factors include:

Pre-existing dry eye
Meibomian gland dysfunction
Contact-lens intolerance
Female sex
Higher refractive correction
Larger ablation depth
Reduced corneal sensation
Autoimmune disease
Certain medications
Prolonged screen use

Treating Dry Eye

Management may include:

Preservative-free artificial tears
Lubricating gel
Warm compresses
Lid hygiene
Treatment of meibomian gland dysfunction
Anti-inflammatory eye drops
Punctal plugs
Autologous serum
Scleral lenses
Specialised pain treatment in severe cases

Femto-LASIK Versus SMILE for Dry Eye

On average, SMILE appears to preserve corneal sensation and tear-film stability better during early recovery because it avoids the large flap side cut.

Meta-analysis found better tear-break-up time, corneal sensitivity and early nerve density after SMILE than after femtosecond LASIK. This is an average group difference and does not mean that every SMILE patient has less dryness or that every Femto-LASIK patient develops dry eye.

Glare, Halos and Starbursts

Possible night-time symptoms include:

Rings around lights
Star-shaped rays
Headlight glare
Ghost images
Smearing
Reduced contrast

Possible causes include:

Dry eye
Residual refractive error
Higher-order aberrations
Large pupils
Optical-zone limitations
Decentration
Healing

Symptoms often improve during the first several months.

Under-Correction and Over-Correction

The achieved result may differ from the intended target.

Possible causes include:

Measurement variation
Biological healing
Laser-tissue interaction
Tear-film instability
Treatment centration
Higher prescription
Hyperopic regression
Astigmatic-axis error

Management may include:

Observation
Spectacles
Contact lenses
Enhancement
Ocular-surface treatment

Regression

Regression means that part of the refractive error returns after an initially successful result.

Possible contributors include:

High preoperative prescription
Corneal healing
Epithelial remodelling
Continuing axial myopia
Hyperopic treatment
Age-related lens changes

Long-term studies show that Femto-LASIK remains effective for many patients but does not prevent later biological changes in the eye.

Enhancement Surgery

An enhancement may be considered when:

A meaningful residual prescription remains
Refraction is stable
Dry eye has been treated
Corneal tomography remains satisfactory
Adequate stromal tissue remains
The expected benefit exceeds the added risk

Options may include:

Lifting the original flap
Surface ablation over the flap
Spectacles or contact lenses
An intraocular procedure in selected cases

Lifting an Old Flap

A LASIK flap can sometimes be lifted months or years later.

However, the risk of epithelial ingrowth rises when an older flap is lifted.

Surface ablation may therefore be preferred for selected late enhancements.

Femtosecond-Laser-Specific Intraoperative Effects

Suction Loss

Suction may be lost if:

The eye moves significantly
The patient squeezes
Docking is unstable
Fluid interferes with the interface
The suction system disengages

Management depends on how much of the flap has been created.

The procedure may be:

Re-docked
Restarted
Reprogrammed
Postponed
Converted to another technique

Opaque Bubble Layer

An opaque bubble layer occurs when gas from photodisruption accumulates within or around the flap.

It may:

Obscure iris-registration features
Interfere with pupil tracking
Make flap lifting more difficult
Temporarily whiten part of the cornea

It usually clears without permanent effect.

Vertical Gas Breakthrough

Rarely, gas may track towards the epithelial surface.

This is more likely when:

A corneal scar is present
Bowman’s layer is disrupted
Laser energy or depth is inappropriate

The flap may become incomplete or irregular.

Anterior-Chamber Gas Bubbles

Tiny bubbles may rarely enter the anterior chamber.

These can interfere temporarily with pupil tracking or laser registration.

The surgeon may wait for the bubbles to clear before completing treatment.

Femtosecond Rainbow Glare

Some patients describe rainbow-like bands around bright lights after femtosecond-laser flap creation.

This has been attributed to diffraction from the regular laser-spot pattern on the back surface of the flap.

Modern energy settings and laser parameters have reduced its frequency.

Symptoms often improve, but persistent cases require assessment.

Transient Light-Sensitivity Syndrome

Transient light-sensitivity syndrome causes pronounced light sensitivity after an initially comfortable recovery.

The cornea may appear relatively normal on examination.

It is considered a rare non-infectious complication associated with femtosecond-laser treatment.

It commonly responds to steroid treatment.

Flap-Related Complications

Incomplete Flap

An incomplete flap may result from:

Suction loss
Docking difficulty
Laser interruption
Corneal scarring
Gas breakthrough

The surgeon may postpone the excimer treatment and allow the cornea to recover before selecting another procedure.

Flap Tear

The flap may tear during lifting or repositioning.

Small peripheral tears may not affect vision.

Larger or central tears may cause:

Irregular astigmatism
Scarring
Delayed recovery
Reduced corrected vision

Flap Striae

Striae are folds within the flap.

Fine peripheral folds may be visually insignificant.

Central or significant folds may cause:

Blurred vision
Ghosting
Irregular astigmatism
Loss of corrected vision

Treatment may involve:

Flap lifting
Smoothing
Stretching
Irrigation
Repositioning

Flap Displacement

The flap may shift after:

Eye rubbing
Direct trauma
Accidental contact
Poor early adherence

Symptoms may include:

Sudden blur
Pain
Watering
Light sensitivity
Foreign-body sensation

Prompt repositioning generally provides a good outcome.

Can the Flap Move Years Later?

The flap edge heals, but the central interface does not regain the full strength of untouched corneal tissue.

Late traumatic flap displacement is uncommon but can occur years after significant direct eye trauma.

Protective eyewear is important for:

Contact sports
Combat sports
Hazardous work
Activities involving projectiles

Diffuse Lamellar Keratitis

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

It may appear as fine white granular cells beneath the flap.

Possible symptoms include:

Haze
Blurred vision
Light sensitivity
Mild discomfort

Early treatment commonly involves intensive steroid drops.

More severe cases may require flap lifting and interface irrigation.

Published reviews report DLK rates ranging from approximately 0.4% to 4.38% across different refractive-surgery series, with variation according to platform, diagnostic threshold and clinical protocol.

Central Toxic Keratopathy

Central toxic keratopathy is a rare non-infectious condition characterised by:

Central stromal haze
Corneal flattening
Hyperopic shift
Stromal striae
Apparent tissue loss

It must be distinguished from DLK because intensive steroid treatment is not managed in the same way.

Current reviews describe central toxic keratopathy, DLK and transient light-sensitivity syndrome as separate inflammatory or toxic disorders.

Epithelial Ingrowth

Surface epithelial cells may grow beneath the flap edge.

It is more common after:

Flap relifting
Flap trauma
Epithelial defects
Older age
Previous epithelial ingrowth

Small peripheral areas may be observed.

Treatment may be required when ingrowth:

Progresses
Approaches the visual axis
Causes irregular astigmatism
Produces flap melting
Reduces vision

Interface Debris

Small particles may be trapped beneath the flap.

Examples include:

Fibres
Meibomian secretions
Metallic particles
Epithelial cells
Surgical debris

Most peripheral debris is harmless.

Central or inflammatory debris may require interface irrigation.

Interface Fluid Syndrome

Raised eye pressure can occasionally force fluid into the LASIK interface.

This may cause:

Hazy vision
An apparently thickened cornea
A falsely low central eye-pressure reading
Misdiagnosis as inflammation

The underlying raised pressure requires prompt recognition and treatment.

Infection

Microbial keratitis after LASIK is rare but potentially sight-threatening.

Possible symptoms include:

Increasing pain
Increasing redness
Worsening vision
Thick discharge
Marked light sensitivity
A white corneal spot

Urgent treatment may require:

Intensive antimicrobial drops
Flap lifting
Interface irrigation
Microbiological sampling
Flap removal in severe cases

Early recognition is essential because infectious and sterile interface inflammation may initially appear similar.

Corneal Ectasia

Corneal ectasia is progressive thinning and bulging of the cornea.

It may cause:

Increasing myopia
Increasing astigmatism
Ghosting
Reduced corrected vision
Irregular tomography
Contact-lens dependence

Why Can Ectasia Occur?

LASIK changes corneal biomechanics by:

Creating a flap through the stronger anterior corneal layers
Removing additional stromal tissue beneath the flap

Risk factors include:

Undiagnosed keratoconus
Suspicious tomography
Abnormal thickness distribution
Inadequate residual stromal bed
High percentage of tissue altered
Young age
High correction
Eye rubbing
Genetic predisposition

A systematic review estimated reported ectasia in eyes without identifiable preoperative risk factors at approximately 90 per 100,000 LASIK-treated eyes. This estimate is limited by under-reporting, variable screening standards and differences in follow-up.

A separate review of more than 30,000 LASIK cases confirmed that post-LASIK ectasia is uncommon but clinically important.

Does a Femtosecond Flap Prevent Ectasia?

No.

A predictable thin flap may improve tissue planning, but Femto-LASIK still creates a stromal flap and removes stromal tissue.

Normal tomography, appropriate tissue calculations and careful patient selection remain essential.

Treating Ectasia

Management may include:

Corneal cross-linking
Spectacles
Rigid contact lenses
Scleral lenses
Intracorneal ring segments
Topography-guided surface treatment
Corneal transplantation in advanced cases

Loss of Corrected Vision

Rarely, an eye may not see as clearly with spectacles after surgery as it did beforehand.

Possible causes include:

Irregular astigmatism
Infection
Scarring
Ectasia
Flap folds
Decentration
Severe dry eye
Interface inflammation

The risk is low in carefully selected patients but cannot be reduced to zero.

Persistent Ocular Pain

A small proportion of patients may experience persistent:

Burning
Aching
Light sensitivity
Wind sensitivity
Pain disproportionate to visible surface findings

Possible causes include:

Severe dry eye
Corneal nerve dysfunction
Neuropathic corneal pain
Central pain sensitisation

Persistent pain deserves specialist evaluation and should not be dismissed merely because the cornea appears relatively clear.

Femto-LASIK Versus Microkeratome LASIK

Both procedures use an excimer laser to correct the prescription.

The difference is how the flap is created.

Possible Advantages of Femto-LASIK

More predictable flap thickness
More uniform flap architecture
Programmable diameter
Programmable hinge
Programmable side-cut angle
Lower risk of free caps or blade-related buttonholes
Ability to create relatively thin planar flaps
Potentially fewer induced aberrations

Possible Advantages of Microkeratome LASIK

Short flap-creation time
Lower equipment cost
No femtosecond gas-related effects
Historically extensive clinical experience

Final Visual Results

Meta-analyses generally show similar:

Unaided vision
Safety
Refractive accuracy

Femtosecond LASIK provides greater flap predictability but may be associated with more DLK in some datasets.

Femto-LASIK Versus SMILE

Both procedures use a femtosecond laser, but they are structurally different.

Femto-LASIK creates a flap and uses an excimer laser.

SMILE creates and removes a stromal lenticule through a small incision.

Possible Advantages of Femto-LASIK

Faster early visual recovery
Established eye tracking
Cyclotorsion compensation
Wavefront- or topography-guided treatment options
Broader treatment of hyperopia
Easier enhancement through flap relifting

Possible Advantages of SMILE

No large hinged flap
Smaller incision
Better early preservation of corneal sensitivity
Fewer flap-trauma concerns
Potentially fewer early dry-eye effects

Overall efficacy, safety and predictability are broadly comparable for myopia and myopic astigmatism, although particular studies report differences in astigmatism, aberrations or recovery.

Femto-LASIK Versus PRK

Both procedures use an excimer laser.

PRK removes the surface epithelium without creating a permanent flap.

Possible Advantages of Femto-LASIK

Faster visual recovery
Less early pain
Faster return to work
Lower risk of corneal haze
Easier enhancement

Possible Advantages of PRK

No permanent flap
No flap-displacement risk
More residual load-bearing stromal tissue for an equivalent correction
May suit selected thinner corneas
May suit contact-sport participants

Limitations of PRK

More early discomfort
Slower recovery
Bandage contact lens
Risk of haze
Longer steroid course

Long-term studies support the safety and effectiveness of both PRK and Femto-LASIK when appropriately selected.

Femto-LASIK Versus ICL

An implantable collamer lens is placed inside the eye without removing the natural lens.

Possible Advantages of Femto-LASIK

No intraocular implant
No intraocular surgery
No ICL sizing or vault concerns
No implant-related cataract risk
Rapid recovery

Possible Advantages of ICL

No corneal stromal tissue removal
Suitable for high myopia
Often excellent optical quality
Removable or exchangeable
Useful when the cornea is unsuitable for laser treatment

ICL may be preferred when:

The prescription is high
The cornea is thin
Tissue removal would be excessive
Corneal shape is unsuitable
Optical-quality preservation is a major priority

Femto-LASIK for Athletes

Femto-LASIK may be suitable for many athletes.

Patients involved in:

Boxing
Martial arts
Rugby
Combat sports
Activities with frequent facial impact

should discuss the permanent flap and consider flap-free alternatives such as PRK or SMILE.

Protective eyewear remains important after every refractive procedure.

Femto-LASIK for Pilots or Military Personnel

Occupational requirements differ between organisations.

Patients should confirm the rules of their:

Employer
Military service
Aviation authority
Licensing body
Professional organisation

before undergoing surgery.

Femto-LASIK and Presbyopia

Femto-LASIK does not stop the natural lens from ageing.

Possible strategies include:

Both eyes corrected for distance with reading glasses
Monovision
Mini-monovision
Leaving mild myopia intentionally
Considering a lens-based procedure

Cataract Surgery After Femto-LASIK

Patients who undergo Femto-LASIK may still develop cataracts later.

Previous laser treatment alters the relationship between the front and back corneal surfaces.

This makes intraocular-lens power calculation more challenging.

Patients should retain:

Preoperative spectacle prescription
Preoperative corneal measurements
Operative report
Laser-treatment details

Modern post-refractive formulas improve accuracy, but refractive prediction remains less straightforward than in an untreated cornea.

Glaucoma Assessment After Femto-LASIK

Conventional eye-pressure readings may underestimate pressure after myopic LASIK.

Glaucoma assessment should also consider:

Optic-nerve appearance
OCT nerve-fibre measurements
Visual fields
Corneal thickness
Alternative pressure methods

Retinal Risk After Femto-LASIK

Femto-LASIK corrects corneal focusing power but does not shorten a highly myopic eye.

The patient may remain at increased risk of:

Retinal tears
Retinal detachment
Myopic macular degeneration
Macular schisis
Glaucoma

Urgent assessment is required for:

New flashes
A sudden increase in floaters
A curtain or shadow
Sudden visual loss

Common Myths

“Femto-LASIK Uses Only One Laser”

False.

A femtosecond laser creates the flap and an excimer laser reshapes the cornea.

“Bladeless Means Risk-Free”

False.

Femto-LASIK avoids blade-related flap creation but still has possible flap, interface, dry-eye and ectasia complications.

“The Flap Heals Back Completely”

False.

The flap edge heals, but the central interface does not regain the same structural strength as untouched cornea.

“The Flap Can Fall Off During Normal Daily Life”

False.

The flap is stable during ordinary life once properly healed.

Significant direct trauma can rarely displace it.

“Femto-LASIK Cannot Cause Dry Eye”

False.

Corneal nerves are disrupted during flap creation and stromal ablation.

“Femto-LASIK Cannot Cause Ectasia”

False.

The risk is low but not zero.

“A Thin Femtosecond Flap Makes Every Thin Cornea Safe”

False.

Corneal shape, residual tissue and biomechanics remain essential.

“The Laser Can Slip if I Move”

Modern lasers track or stabilise the eye.

The laser can pause when alignment is lost.

“Femto-LASIK Prevents Presbyopia”

False.

The natural lens continues ageing.

“Femto-LASIK Stops Myopia Permanently”

False.

The corneal correction is permanent, but the eye may continue changing.

“Correcting High Myopia Removes Retinal Risk”

False.

The eye remains anatomically myopic.

“Newer Technology Guarantees a Perfect Result”

False.

Outcomes depend on:

Patient selection
Measurements
Treatment planning
Surgeon experience
Ocular-surface management
Postoperative care

Frequently Asked Questions

Is Femto-LASIK Safer Than LASIK?

Femto-LASIK is LASIK using a femtosecond-created flap.

It offers more predictable flap construction than mechanical LASIK but still carries LASIK-related risks.

Is Femto-LASIK Better Than SMILE?

Neither is universally better.

Femto-LASIK may offer:

Faster early visual recovery
Greater customisation
Easier enhancement

SMILE may offer:

No large flap
Less early nerve disruption
Fewer flap-trauma concerns

Is Femto-LASIK Better Than PRK?

Femto-LASIK generally recovers faster and causes less early pain.

PRK avoids a permanent flap and may be preferable for selected thin corneas or trauma-risk occupations.

Am I Too Short-Sighted for Femto-LASIK?

Suitability depends on more than the spectacle prescription.

The surgeon must consider:

Corneal thickness
Corneal shape
Flap thickness
Ablation depth
Optical zone
Residual stromal bed
Retinal health
Alternative options such as ICL

Can Femto-LASIK Correct Astigmatism?

Yes.

Regular astigmatism can often be corrected effectively.

A small residual amount may remain.

Can Both Eyes Be Treated on the Same Day?

Yes.

This is common when both eyes are suitable.

Can I Blink During the Procedure?

An eyelid holder prevents blinking.

Can I See the Laser?

The patient sees fixation lights and brightness but does not see the detailed surgical steps clearly.

What Happens if Suction Is Lost?

The surgeon assesses how much flap creation has occurred.

The procedure may be re-docked, restarted, postponed or converted.

Can the Flap Be Made Too Thin or Too Thick?

Femtosecond flaps are generally predictable, but some variation remains possible.

This is why flap thickness and residual tissue are planned with safety margins.

Can I Rub My Eyes?

Eye rubbing should be avoided during early healing.

Long-term vigorous rubbing is also discouraged because it may:

Injure the flap
Worsen allergy
Irritate the ocular surface
Stress the cornea

When Can I Wash My Face?

Gentle washing is usually possible, but water, soap and pressure should be kept away from the eyes during early recovery.

When Can I Resume Contact Sports?

The timeline depends on the sport and healing.

Patients involved in direct facial-impact sports should discuss whether a flap-free procedure is preferable before surgery.

Can Femto-LASIK Be Reversed?

No.

The flap can be lifted, but stromal tissue removed by the excimer laser cannot simply be replaced.

Can I Have Femto-LASIK Again?

An enhancement may be possible if:

Refraction is stable
Corneal shape remains normal
Adequate stromal tissue remains
The expected benefit justifies the risk

Will I Need Reading Glasses?

Patients approaching presbyopic age should expect near vision to become more difficult unless monovision is selected.

Even with monovision, spectacles may be needed for fine reading.

Can Femto-LASIK Cause Blindness?

Severe permanent visual loss is very rare.

Possible causes include:

Infection
Severe ectasia
Corneal scarring
Uncontrolled inflammation
Other unrelated eye disease

The risk is small but not zero.

Can I Wear Contact Lenses Again?

Yes, if required.

Contact lenses may be used for:

Residual refractive error
Irregular astigmatism
Ectasia
Special visual tasks

Does Femto-LASIK Change Eye Colour?

No.

The iris is not treated.

Can Femto-LASIK Treat Lazy Eye?

No.

It corrects refractive error but does not reverse amblyopia developed during childhood.

Can I Have Cataract Surgery Later?

Yes.

The cataract surgeon should use post-refractive intraocular-lens calculation methods.

When to Seek Urgent Eye Care

Seek urgent assessment for:

Increasing pain
Increasing redness
Rapidly worsening vision
Thick discharge
Marked light sensitivity
A white corneal spot
Sudden flap displacement
Significant eye trauma
Vision worsening after initial improvement
New flashes or floaters
A curtain or shadow
Severe headache or nausea with eye symptoms

Severe pain or worsening vision should never be assumed to be ordinary dry eye.

A Femto-LASIK Assessment Checklist

Visual Goals to Discuss

Distance vision
Near vision
Computer use
Night driving
Sports
Occupation
Spectacle independence
Monovision
Tolerance of glare or halos

Medical Information to Report

Diabetes
Autoimmune disease
Thyroid disease
Pregnancy or breastfeeding
Allergies
Migraine
Chronic pain
Medication
Previous healing problems

Eye History to Report

Dry eye
Contact-lens intolerance
Eye rubbing
Keratoconus in the family
Recurrent corneal erosion
Herpetic eye disease
Glaucoma
Retinal tears
Eye trauma
Previous eye surgery

Tests That May Be Used

Unaided and corrected vision
Manifest refraction
Cycloplegic refraction
Corneal topography
Corneal tomography
Pachymetry
Epithelial thickness mapping
Corneal biomechanics
Wavefront aberrometry
Tear-film assessment
Pupil and centration measurements
Eye-pressure testing
Dilated retinal examination

Questions to Ask the Surgeon

Am I genuinely suitable for Femto-LASIK?
Is my corneal tomography completely normal?
Is my prescription stable?
What flap thickness and diameter are planned?
How much residual stromal tissue will remain?
What is my percentage of tissue altered?
Which excimer treatment profile will be used?
Would SMILE, PRK or ICL be safer?
What visual result is realistic?
How likely am I to need reading spectacles?
Should I consider monovision?
What is my risk of dry eye?
What is my risk of flap complications?
What is my risk of ectasia?
How would residual prescription be treated?
What warning symptoms require urgent review?
How frequently will I be examined afterwards?

The Bottom Line

Femto-LASIK is a laser vision-correction procedure that uses:

A femtosecond laser to create a corneal flap
An excimer laser to reshape the underlying corneal stroma

It may correct:

Myopia
Hyperopia
Astigmatism
Presbyopia through monovision in selected patients

Potential advantages include:

Rapid visual recovery
Little pain during surgery
Predictable flap thickness
Customisable flap dimensions
No mechanical blade
Availability of wavefront- and topography-guided treatment
Easier enhancement than some flap-free procedures

Possible disadvantages include:

A permanent corneal flap
Dry-eye symptoms
Glare and halos
Risk of traumatic flap displacement
Interface complications
Removal of load-bearing stromal tissue

Possible complications include:

Suction loss
Incomplete flap creation
Flap folds
Flap displacement
Diffuse lamellar keratitis
Epithelial ingrowth
Infection
Residual refractive error
Regression
Corneal ectasia
Rare loss of corrected vision

Femto-LASIK offers more predictable flap creation than traditional microkeratome LASIK, but final visual outcomes may be similar when either procedure is performed well.

SMILE may be preferable when avoiding a large flap and reducing early nerve disruption are priorities.

PRK may be preferable for selected thinner corneas or trauma-risk occupations.

ICL may be more appropriate for high prescriptions or corneas unsuitable for tissue-removing laser surgery.

The most important message is:

The femtosecond laser improves control over flap creation, but it does not make every patient suitable for LASIK. The best results depend on normal corneal structure, accurate measurements, appropriate tissue calculations, a healthy ocular surface, realistic expectations and careful postoperative follow-up.

References

Moshirfar M, Bennett P, Ronquillo Y. Complications of laser-assisted in situ keratomileusis. Indian J Ophthalmol. 2021;69(7):1658–1669. PMID: 34146007.
Chen S, Feng Y, Stojanovic A, Jankov MR, Wang Q. IntraLase femtosecond laser versus mechanical microkeratomes in LASIK for myopia: a systematic review and meta-analysis. J Refract Surg. 2012;28(1):15–24. PMID: 22233436.
Zhang ZH, Jin HY, Suo Y, et al. Femtosecond laser versus mechanical microkeratome LASIK for myopia: meta-analysis of randomised controlled trials. J Cataract Refract Surg. 2011;37(12):2151–2159. PMID: 22108110.
Rattan SA, Rashid RF, Mutashar MK, Nasser YAR, Anwar DS. Comparison of corneal flap thickness predictability and architecture between femtosecond laser and microkeratome LASIK. Int Ophthalmol. 2023;43(5):1553–1558. PMID: 36307607.
Cummings AB, Cummings BK, Kelly GE. Predictability of corneal flap thickness in LASIK using a 200-kHz femtosecond laser. J Cataract Refract Surg. 2013;39(3):378–385. PMID: 23352500.
Ju WK, Lee JH, Chung TY, Chung ES. Reproducibility of LASIK flap thickness using a femtosecond laser measured by OCT. J Refract Surg. 2011;27(2):106–110. PMID: 20481410.
Yuen LHY, Chan WK, Koh J, Mehta JS, Tan DTH. A 10-year prospective audit of LASIK outcomes for myopia in 37,932 eyes at a single institution in Asia. Ophthalmology. 2010;117(6):1236–1244.e1. PMID: 20153899.
Eydelman M, Hilmantel G, Tarver ME, et al. Symptoms and satisfaction of patients in the Patient-Reported Outcomes With LASIK studies. JAMA Ophthalmol. 2017;135(1):13–22. PMID: 27893066.
Brunson PB, et al. Patient-reported visual outcomes, dry-eye symptoms and satisfaction following topography-guided LASIK. Clin Ophthalmol. 2025. PMID: 40963955.
Sambhi RDS, Sambhi GDS, Mather R, Malvankar-Mehta MS. Dry eye after refractive surgery: a meta-analysis. Can J Ophthalmol. 2020;55(2):99–106. PMID: 31712000.
Kobashi H, Kamiya K, Shimizu K. Dry eye after SMILE and femtosecond laser-assisted LASIK: meta-analysis. Cornea. 2017;36(1):85–91. PMID: 27560032.
Bohac M, Koncarevic M, Pasalic A, et al. Incidence and clinical characteristics of post-LASIK ectasia: a review of over 30,000 cases. Semin Ophthalmol. 2018;33(7–8):869–877. PMID: 30359155.
Moshirfar M, Tukan AN, Bundogji N, et al. Ectasia after corneal refractive surgery: a systematic review. Ophthalmol Ther. 2021;10(4):753–776. PMID: 34417707.
Chang EK, Pineda R II. Noninfectious inflammatory complications of lamellar refractive corneal surgery. Int Ophthalmol Clin. 2025;65(3):71–76. PMID: 40601513.
Sharma N, et al. Keratitis following laser refractive surgery: clinical spectrum, prevention and management. Indian J Ophthalmol. 2020;68(12):2813–2818. PMID: 33229656.
Liu M, et al. One-year refractive outcomes of femtosecond LASIK in mild, moderate and high myopia. Int Ophthalmol. 2018. PMID: 29450367.
Jiménez JR, et al. Twelve-month visual and refractive outcomes of topography-guided femtosecond LASIK for myopia and myopic astigmatism. J Refract Surg. 2024. PMID: 39254246.
Gershoni A, et al. Long-term follow-up safety and effectiveness of myopia refractive surgery. Int J Environ Res Public Health. 2020;17(23):8725. PMID: 33255392.
Reinstein DZ, Archer TJ, Gobbe M. LASIK interface complications: aetiology, management and outcomes. J Refract Surg. 2012;28(8):575–586.
Vestergaard AH, et al. Patient satisfaction following femtosecond LASIK and SMILE for myopia. Clin Ophthalmol. 2018;12:1745–1754. PMID: 30237694.