LASIK vs PRK: Which Laser Vision Correction Procedure Is Better?

Author: Dr Val Phua
Estimated reading time: 17 minutes

LASIK and Photorefractive Keratectomy—commonly known as PRK—are established laser vision correction procedures used to reduce dependence on spectacles and contact lenses.

Both use an excimer laser to permanently reshape the cornea so that light focuses more accurately on the retina.

The main difference is how the surgeon reaches the corneal tissue being reshaped:

LASIK creates a thin, hinged corneal flap. The excimer laser reshapes the tissue beneath the flap, which is then repositioned.
PRK removes the thin surface epithelial layer without creating a flap. The excimer laser reshapes the exposed corneal surface, and the epithelium grows back over several days.

In suitable patients, LASIK and PRK generally provide similarly good final visual acuity, refractive accuracy and long-term safety. LASIK offers faster visual recovery and less early discomfort. PRK avoids flap-related risks and preserves more of the anterior corneal structure, but recovery is slower and corneal haze is a specific concern. [1–4]

Neither procedure is universally better.

The appropriate choice depends on:

Corneal thickness and shape
Degree of refractive error
Dry-eye status
Occupation and sporting activities
Risk of eye trauma
Previous eye surgery
Healing characteristics
Willingness to accept a slower recovery
The need for customised treatment
The possibility of future enhancement

LASIK vs PRK at a Glance

LASIK May Be Favoured When:

Rapid visual recovery is a priority
Minimal postoperative discomfort is important
The cornea is sufficiently thick and regularly shaped
Dry-eye disease is controlled
There is a low risk of significant eye trauma
A straightforward enhancement pathway is desirable
Wavefront- or topography-guided correction is planned

PRK May Be Favoured When:

Avoiding a corneal flap is important
The cornea is relatively thin but remains suitable for surface ablation
The patient participates in contact or combat sports
Occupational eye trauma is a concern
Previous corneal surgery makes a flap less desirable
Surface-based customised treatment is preferred
The patient can accept several uncomfortable days and a slower visual recovery

What Is LASIK?

LASIK stands for Laser-Assisted In Situ Keratomileusis.

Modern femtosecond LASIK generally involves two lasers:

A femtosecond laser creates a thin, hinged corneal flap.
The surgeon lifts the flap.
An excimer laser reshapes the underlying corneal stroma.
The flap is repositioned over the treatment area.

For myopia, the excimer laser removes more tissue centrally, flattening the cornea.

For hyperopia, treatment is applied more peripherally to make the central cornea relatively steeper.

For astigmatism, different amounts of tissue are removed along different meridians.

The LASIK flap usually remains in place without stitches. The surface seals quickly, but a permanent tissue interface remains within the cornea. FDA guidance describes LASIK as an effective but irreversible procedure that may cause undercorrection, overcorrection, glare, halos, dry eye or loss of lines of best-corrected vision in a small proportion of patients. [5,6]

What Is PRK?

PRK stands for Photorefractive Keratectomy.

During PRK:

The corneal epithelium is removed.
The excimer laser reshapes the tissue at the front of the corneal stroma.
Medication such as mitomycin C may be applied when clinically appropriate.
A soft bandage contact lens is placed over the cornea.
The epithelium grows back beneath the contact lens over the following days.

No LASIK flap is created.

The excimer-laser treatment can use many of the same planning approaches available for LASIK, including:

Standard treatment
Wavefront-optimised treatment
Wavefront-guided treatment
Topography-guided treatment
Aspheric treatment profiles

PRK has a longer and less comfortable initial recovery because the corneal surface must regenerate. Nevertheless, long-term corrected and unaided vision is generally comparable with LASIK in appropriately selected patients. [1,3,7]

What Is the Main Difference Between LASIK and PRK?

The main difference is whether a corneal flap is created.

LASIK

A flap is created
The laser treatment is placed beneath the flap
The surface epithelium is largely preserved
Vision recovers rapidly
Early pain is usually mild
Permanent flap-related considerations remain

PRK

No flap is created
The surface epithelium is removed
The laser treatment is applied directly to the anterior stroma
The epithelium must regrow
Recovery is slower and more uncomfortable
There is no permanent flap to displace

The excimer laser performs the refractive reshaping in both procedures.

Does PRK Remove More Tissue Than LASIK?

The excimer-laser ablation required to correct a given prescription may be similar when the same optical zone and treatment profile are used.

However, LASIK also requires the creation of a flap.

The flap tissue remains physically present, but most of it does not contribute fully to the strength of the deeper residual stromal bed. PRK does not require this additional flap-related separation.

PRK may therefore leave a thicker effective load-bearing stromal bed than LASIK for the same correction.

This does not mean that every thin cornea is suitable for PRK. PRK still permanently removes stromal tissue and can cause ectasia when performed in an unsuitable or structurally vulnerable cornea. [8,9]

Which Gives Better Final Vision?

For low-to-moderate myopia in properly selected patients, the final results are generally similar.

Studies comparing LASIK and PRK have found broadly comparable:

Unaided distance visual acuity
Best-corrected visual acuity
Refractive accuracy
Safety
Long-term patient satisfaction

A Cochrane review found that LASIK provided faster recovery and less pain but that outcomes were similar approximately one year after surgery. A 2025 meta-analysis similarly found no significant overall clinical advantage of LASIK over PRK, apart from less early haze after LASIK. [1,4]

The quality of the result depends on more than the procedure name.

Important factors include:

Accurate refraction
Stable prescription
Corneal topography and tomography
Laser platform
Treatment centration
Optical-zone diameter
Tear-film health
Postoperative healing
Compliance with medication and follow-up

Which Has Faster Visual Recovery?

LASIK generally has much faster initial visual recovery.

Many patients notice substantially clearer vision within hours and have functional vision by the following day.

PRK vision is usually blurred during the first several days because the epithelium is regenerating. Vision then improves progressively over the following weeks.

A typical functional pattern is:

LASIK

Significant improvement within the first day
Office-based work often possible within one to three days
Fine visual quality may continue improving over several weeks

PRK

Blurred vision during early epithelial healing
Functional improvement over approximately one to two weeks
Fluctuation may continue for several weeks
Maximum clarity may take one to three months or longer, especially after higher corrections

Randomised and systematic-review evidence consistently shows faster early visual recovery after LASIK. [1,10]

Which Procedure Is More Painful?

PRK is more uncomfortable during the early recovery period.

The epithelium contains many nerve endings. Until it has regenerated, patients may experience:

Burning
Stinging
Watering
Light sensitivity
A gritty or foreign-body sensation
Difficulty opening the eyes
Eyelid swelling
Fluctuating vision

Discomfort is usually most noticeable during the first two to three days and improves as the epithelium heals.

A bandage contact lens protects the regenerating surface and is usually removed after the epithelium has closed.

LASIK commonly causes:

Watering
Mild burning
Grittiness
Light sensitivity

during the first several hours, but significant pain is less common. A randomised bilateral comparison found markedly less first-day pain after LASIK than PRK. [10]

What Is the PRK Recovery Timeline?

Recovery varies according to the prescription, healing response and epithelial-removal technique.

The First 24 Hours

Patients may notice:

Blurred vision
Watering
Burning or stinging
Significant light sensitivity
Grittiness
Difficulty keeping the eyes open

Prescribed medication may include:

Antibiotic eyedrops
Steroid eyedrops
Lubricants
Oral or topical pain relief
Other medication according to the surgeon’s protocol

Days Two to Four

The epithelium continues growing across the treatment area.

Discomfort usually improves gradually but may fluctuate.

The bandage contact lens remains in place unless the surgeon advises otherwise.

Days Four to Seven

Once the epithelium has healed adequately, the bandage contact lens can usually be removed.

Vision may still be hazy or inconsistent.

Weeks One to Four

Vision becomes progressively clearer.

Patients may notice:

Fluctuation
Mild haze
Dryness
Glare
Halos
Different recovery rates between the two eyes

One to Three Months

Vision usually becomes more stable.

Higher corrections, haze or ocular-surface problems may lengthen the recovery period.

Steroid eyedrops are often continued longer after PRK than after LASIK to control inflammation and reduce haze risk.

What Is the LASIK Recovery Timeline?

The First Few Hours

Patients may experience:

Watering
Mild burning
Light sensitivity
Blurred or hazy vision
A sensation of something in the eye

Resting with the eyes closed is often helpful.

The Following Day

Many patients have functional distance vision.

The surgeon checks:

Flap position
Corneal clarity
Inflammation
Eye pressure
Vision
The ocular surface

The First Week

Vision generally continues to stabilise.

Patients should avoid:

Eye rubbing
Contaminated water
Eye makeup
Strenuous contact activity
Dusty or dirty environments

The First Month

Dryness, glare or mild fluctuation usually continues to improve.

Which Procedure Causes More Dry Eye?

LASIK generally causes more early corneal nerve disruption.

The LASIK flap cuts across many of the anterior stromal nerves that help regulate:

Corneal sensation
Tear secretion
Blinking
Ocular-surface maintenance

PRK removes the epithelial nerve endings, but the deeper anterior stromal nerve architecture is not separated by a broad flap.

PRK may therefore be preferred for selected patients with dry-eye risk. However, PRK can still cause:

Temporary reduced corneal sensation
Tear-film instability
Burning
Fluctuating vision
Ocular-surface inflammation

Neither procedure should be performed while significant dry-eye disease, blepharitis or meibomian gland dysfunction remains uncontrolled. FDA data have shown that new dry-eye symptoms can occur after LASIK even in patients who did not report them preoperatively. [6,11]

Does PRK Completely Avoid Dry Eye?

No.

The corneal epithelium and superficial nerves are removed during PRK and must regenerate.

Temporary dryness can result from:

Reduced corneal sensation
Frequent postoperative eyedrops
Preservatives
Inflammation
Reduced blinking
Pre-existing eyelid-gland disease

PRK may reduce flap-related nerve disruption, but it does not eliminate ocular-surface symptoms.

What Is Corneal Haze?

Corneal haze is an abnormal healing response in which fibrotic material develops within the treated corneal stroma.

It may cause:

Hazy vision
Glare
Halos
Reduced contrast
Regression of the refractive correction
Reduced best-corrected vision in significant cases

Mild transient haze may be visible during routine examination without causing meaningful symptoms.

Clinically important haze has become less common because of:

Improved laser profiles
Smoother ablation
Appropriate mitomycin C use
Better steroid protocols
Ultraviolet protection
Improved patient selection

Haze remains a PRK-specific concern because the excimer treatment occurs directly beneath the regenerating epithelium. [12,13]

What Is Mitomycin C?

Mitomycin C is an anti-proliferative medication that may be applied briefly to the treated cornea during PRK.

It is used to reduce the activity of cells involved in scar and haze formation.

Its use is particularly considered when:

The correction is relatively high
The ablation is deep
Previous corneal surgery has been performed
Haze risk is otherwise increased

Meta-analyses have found that mitomycin C reduces early- and late-onset PRK haze. However, the concentration and application duration should be individualised because the medication is biologically active and is being used on healthy corneal tissue during elective surgery. [13–15]

Does LASIK Cause Haze?

Significant stromal haze is much less common after uncomplicated LASIK because the surface epithelium remains largely intact and the excimer treatment is performed beneath the flap.

LASIK has different interface-related complications, including:

Diffuse lamellar keratitis
Interface debris
Epithelial ingrowth
Flap folds
Interface infection

LASIK’s lower haze risk is one reason visual recovery is generally faster.

What Is the LASIK Flap?

The flap is a thin layer of corneal tissue created by a femtosecond laser or, less commonly today, a mechanical microkeratome.

Once repositioned, the surface epithelium seals around the flap edge.

The flap is stable for normal daily life, but the deeper interface does not regain the tensile strength of untouched corneal tissue.

Possible flap complications include:

Flap displacement
Flap folds or striae
Epithelial ingrowth
Diffuse lamellar keratitis
Interface debris
Traumatic flap injury

These complications are uncommon, but they are unique to LASIK.

Can the LASIK Flap Move Years Later?

Significant late displacement is rare, but severe direct trauma can disturb a LASIK flap years after surgery.

The possibility is most relevant to people involved in:

Boxing
Martial arts
Rugby
Contact sports
Military activities
Police or security work
Occupations with facial trauma risk

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

Which Is Better for Contact Sports?

PRK is often favoured for patients with substantial long-term risk of direct eye trauma because there is no flap to displace.

This does not make the eye injury-proof.

Trauma can still cause:

Corneal abrasion
Infection
Traumatic inflammation
Cataract
Retinal tear
Retinal detachment

Protective eyewear remains important whenever practical.

Which Procedure Preserves More Corneal Strength?

PRK generally preserves a thicker effective stromal bed because no flap is created.

This may be useful when:

The cornea is relatively thin
A LASIK flap would leave insufficient load-bearing tissue
The planned correction is moderate
Corneal tomography is otherwise reassuring

However, biomechanical safety cannot be determined by a single residual-thickness number.

Assessment should also consider:

Anterior and posterior corneal elevation
Pachymetry distribution
Epithelial thickness
Corneal asymmetry
Percentage of tissue altered
Family history
Age
Eye rubbing
Biomechanical measurements

A systematic review of corneal biomechanical changes supports the concept that different refractive procedures affect the cornea differently, but no current test can guarantee that ectasia will never occur. [8]

Can Corneal Ectasia Occur After PRK?

Yes.

Postoperative corneal ectasia has been reported after both LASIK and PRK.

The reported risk is generally lower after PRK, but this may partly reflect:

Different patient selection
Lower historical treatment ranges
The absence of flap creation
Differences in total procedure numbers
Underreporting
Differences in follow-up

PRK should not be used as a way to treat a structurally suspicious cornea simply because it avoids a flap.

Patients with progressive keratoconus, forme-fruste keratoconus or clearly abnormal tomography are generally unsuitable for routine corneal laser vision correction.

Is PRK Better for Thin Corneas?

Sometimes, but not always.

PRK may be possible when a cornea is too thin for LASIK because it avoids the tissue commitment associated with a flap.

However, the cornea must still have:

Adequate total thickness
Normal or acceptably stable tomography
Adequate residual stromal tissue
No evidence of keratoconus
No concerning epithelial pattern
An acceptable treatment depth

A thin, weak or suspicious cornea may be unsuitable for both procedures.

Alternatives may include:

Implantable Collamer Lens surgery
Spectacles
Contact lenses
No refractive surgery

Which Procedure Can Treat a Wider Prescription Range?

The precise approved ranges depend on:

Laser platform
Country
Treatment profile
Patient anatomy
Surgeon assessment

LASIK is commonly used for:

Myopia
Hyperopia
Myopic astigmatism
Hyperopic astigmatism
Mixed astigmatism
Monovision

PRK can also treat myopia, hyperopia and astigmatism using compatible excimer-laser platforms.

For high myopia, both procedures require substantial tissue removal. The relative advantage of avoiding a flap does not eliminate the concerns of:

Deep ablation
Haze
Regression
Reduced optical-zone quality
Ectasia
Night-vision symptoms

An ICL may be more appropriate when corneal tissue removal would be excessive.

Which Is Better for High Myopia?

LASIK may provide faster recovery and lower haze risk.

PRK avoids a flap but may have:

More postoperative discomfort
Slower recovery
Greater haze concern
Greater refractive regression after high corrections

Older ten-year data found both LASIK and PRK safe for moderate myopia, with LASIK showing slightly better efficacy, predictability and fewer retreatments in that historical cohort. Technology has changed considerably since those procedures were performed, so those numerical results should not be applied directly to modern treatment. [2]

For very high myopia, neither LASIK nor PRK may be the preferred option if the required tissue removal is excessive.

Which Is Better for Astigmatism?

Both LASIK and PRK can treat regular astigmatism using the same or similar excimer-laser platforms.

Accuracy depends on:

Consistency of the measured cylinder
Correct axis alignment
Cyclotorsion control
Eye tracking
Treatment centration
Corneal healing
Magnitude of astigmatism

LASIK may stabilise faster because epithelial healing has less influence on the early refractive result.

PRK can still provide excellent astigmatic correction, but the result may take longer to stabilise.

Which Procedure Is Better for Hyperopia?

LASIK is often favoured for hyperopia because:

Visual recovery is faster
Haze risk is lower
Hyperopic treatments may involve larger peripheral ablation areas
Epithelial remodelling after PRK may influence regression

PRK remains an option for selected hyperopic patients when the cornea and treatment plan are suitable.

Hyperopic correction generally has a greater tendency to regress than low-to-moderate myopic correction, regardless of procedure.

What Is TransPRK?

Transepithelial PRK, or TransPRK, removes the epithelium using the excimer laser rather than a manual instrument or alcohol.

Depending on the platform, the epithelial and refractive treatment may be completed as one programmed sequence.

Potential advantages include:

No alcohol exposure
No mechanical epithelial removal
A standardised treatment process
Reduced instrument contact
Potentially smoother early healing

However, TransPRK remains a form of surface ablation.

It still involves:

Epithelial removal
Postoperative discomfort
A bandage contact lens
Slower recovery than LASIK
Haze risk

A comparative analysis of LASIK, TransPRK and SMILE found broadly similar final efficacy and safety, while TransPRK had the longest and most uncomfortable early recovery. [16]

What Are LASEK and Epi-LASIK?

LASEK and Epi-LASIK are surface-ablation variations.

LASEK

The epithelium is loosened, commonly using dilute alcohol, and moved aside before laser treatment.

Epi-LASIK

An epithelial separator is used to create an epithelial sheet before treatment.

The epithelial tissue may be repositioned, but much of it may not remain viable.

In practice, recovery and risk profiles are broadly similar to PRK because the surface epithelium must still regenerate.

Which Has Better Night Vision?

Most appropriately selected patients have satisfactory night vision after either procedure.

Both can cause:

Glare
Halos
Starbursts
Ghost images
Reduced contrast
Night-driving difficulty

Risk is influenced by:

Pupil size
Treatment zone
Degree of correction
Residual refractive error
Astigmatism
Decentration
Dry eye
Higher-order aberrations
Corneal haze

PRK haze or slow epithelial remodelling may affect early night vision.

LASIK flap and interface effects may influence optical quality in other ways.

There is no universal rule that one procedure always produces better night vision.

Can LASIK or PRK Be Customised?

Yes.

Depending on the platform and the patient’s measurements, either procedure may use:

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

The same planned excimer-laser ablation may sometimes be delivered beneath a LASIK flap or directly to the corneal surface during PRK.

The choice of access method and the choice of laser-treatment profile are related but separate decisions.

What Is Wavefront-Guided Treatment?

Wavefront-guided treatment measures optical aberrations beyond ordinary sphere and cylinder.

The laser pattern is customised to the measured optical system.

Potential goals include:

Reducing induced higher-order aberrations
Improving low-contrast vision
Improving night visual quality
Treating certain optical irregularities

Reliable measurements and suitable anatomy are required.

What Is Topography-Guided Treatment?

Topography-guided treatment uses detailed maps of the corneal surface.

It may be considered for:

Corneal asymmetry
Decentred previous treatment
Selected regular irregularities
Higher-order corneal aberrations
Certain enhancement procedures

Topography-guided treatment should not be used to conceal active or progressive keratoconus.

Which Procedure Is Easier to Enhance?

LASIK often provides a relatively direct early enhancement pathway.

If a residual prescription remains, options may include:

Lifting the flap and applying further excimer treatment
PRK over the flap
Spectacles
Contact lenses

The flap may become more difficult or less desirable to relift many years later because the risk of epithelial ingrowth may increase.

Enhancement After PRK

A PRK enhancement is usually another surface-ablation procedure.

The surgeon must consider:

Remaining corneal thickness
Previous haze
Healing response
Mitomycin C use
Stability of the prescription
Corneal topography and tomography

Recovery again follows a PRK-type timeline.

A large retreatment series found that both flap-lift enhancement and surface ablation could produce similar visual outcomes in selected eyes, although the complication profiles differed. [17]

Can PRK Be Performed After LASIK?

Yes, in selected cases.

PRK over a previous LASIK flap may be used when:

The original flap is old
Flap relifting carries a higher epithelial-ingrowth risk
The residual correction is small
Corneal thickness is adequate
Tomography remains acceptable

Surface enhancement after LASIK has been reported to be safe and effective for selected residual refractive errors. [18]

Can LASIK Be Performed After PRK?

Potentially, but it is not always preferred.

Creating a flap in a previously surface-treated cornea may introduce additional biomechanical and healing considerations.

A repeat surface procedure may be more appropriate depending on:

Corneal thickness
Previous treatment depth
Haze history
Epithelial mapping
Residual prescription
Surgeon judgement

What Are the Main Risks of LASIK?

LASIK risks include:

Dry eye
Under- or overcorrection
Residual astigmatism
Glare and halos
Flap displacement
Flap folds
Epithelial ingrowth
Diffuse lamellar keratitis
Interface infection
Corneal ectasia
Reduced contrast sensitivity
Loss of best-corrected vision
Need for enhancement
Rare persistent neuropathic corneal pain

FDA guidance emphasises that some patients may experience persistent visual symptoms or dryness even when standard visual acuity is good. [6]

What Are the Main Risks of PRK?

PRK risks include:

More postoperative pain
Slower visual recovery
Delayed epithelial healing
Corneal haze
Infection while the epithelium is healing
Steroid-related eye-pressure elevation
Under- or overcorrection
Regression
Residual astigmatism
Glare and halos
Corneal ectasia
Loss of best-corrected vision
Need for enhancement

Mitomycin C, topical steroids and ultraviolet protection have reduced but not eliminated the risk of haze. [12–15]

Is Infection More Common After PRK?

Serious infection is rare after either procedure.

The early infection pathways differ.

After PRK

The corneal surface remains temporarily open until the epithelium regenerates. During this period:

A bandage contact lens is present
The surface barrier is incomplete
Medication adherence and hygiene are essential

After LASIK

The surface epithelium is more intact, but infection can develop within the flap interface.

Increasing pain, redness, discharge, light sensitivity or worsening vision after either procedure requires urgent assessment.

Can Steroid Drops Cause Glaucoma After PRK?

Yes.

Steroid eyedrops are often used for a longer period after PRK than LASIK.

Some patients are steroid responders and develop raised eye pressure.

Pressure should therefore be monitored during postoperative steroid treatment.

Patients should not stop steroids independently because uncontrolled inflammation may increase haze risk.

Does Either Procedure Prevent Presbyopia?

No.

LASIK and PRK reshape the cornea but do not restore the natural crystalline lens’s ability to accommodate.

Patients corrected fully for distance may require reading glasses as presbyopia develops.

Both procedures may be used for monovision:

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

A contact lens trial is advisable before permanent monovision correction.

Are LASIK and PRK Permanent?

Yes.

Both permanently remove corneal tissue.

The removed tissue does not grow back.

However, vision can change because of:

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

A permanent procedure does not guarantee a permanently unchanged prescription.

Which Has Better Long-Term Stability?

Within appropriate treatment ranges, both LASIK and PRK have extensive long-term evidence.

Studies extending to ten years and beyond generally show high safety for both procedures, although regression becomes more relevant after higher corrections. A long-term review concluded that late complications were uncommon and that effectiveness was most likely to decline when early-generation technology was used for high corrections. [2,3]

Modern lasers, larger optical zones, improved eye tracking and better nomograms may produce different results from procedures performed decades ago.

Who May Be Suitable for Either Procedure?

A typical candidate has:

A stable prescription
Adequate refractive maturity
Healthy corneas
Normal or acceptably stable tomography
Adequate corneal thickness
Controlled dry-eye disease
No significant cataract
No active infection or inflammation
Realistic expectations
Willingness to attend follow-up

Who May Not Be Suitable?

LASIK or PRK may be unsuitable when there is:

Progressive keratoconus
Suspicious corneal tomography
Inadequate residual stromal tissue
Severe uncontrolled dry eye
Active blepharitis
Active eye infection
Unstable refraction
Pregnancy or breastfeeding
Uncontrolled systemic disease affecting healing
Significant cataract
Vision-limiting retinal or optic nerve disease
Unrealistic expectations

FDA guidance also advises caution in patients with conditions that may impair healing or increase the risk of poor visual outcomes. [6,19]

What Tests Are Required Before LASIK or PRK?

Refraction and Visual Acuity

This determines:

Myopia or hyperopia
Astigmatism
Best-corrected vision
Prescription stability

Corneal Topography and Tomography

These scans assess:

Corneal curvature
Front and back elevation
Pachymetry distribution
Keratoconus risk
Corneal asymmetry
Treatment centration

Corneal Thickness

The surgeon calculates:

Expected ablation depth
Flap thickness for LASIK
Residual stromal tissue
Percentage of tissue altered

Epithelial Thickness Mapping

This may identify:

Early keratoconus patterns
Contact lens warpage
Localised epithelial compensation
Previous treatment changes

Corneal Biomechanical Assessment

Additional testing may provide information about how the cornea deforms under pressure.

No biomechanical test can guarantee the absence of future ectasia.

Dry-Eye and Eyelid Assessment

The surgeon evaluates:

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

Pupil Size

Pupil measurements help with counselling about:

Optical-zone planning
Glare
Halos
Night vision

Eye Pressure and Optic Nerve

Glaucoma or ocular hypertension should be identified before surgery.

Dilated Retinal Examination

This is particularly important in moderate and high myopia.

Laser correction does not remove the retinal risks associated with an elongated myopic eye.

LASIK May Be the Better Choice When:

The fastest possible recovery is important
The patient cannot tolerate several painful recovery days
The cornea is sufficiently thick and structurally normal
Dry eye is well controlled
There is little risk of direct ocular trauma
Hyperopia is being treated
Easy enhancement is important
Flap-specific risks are acceptable

PRK May Be the Better Choice When:

Avoiding a flap is important
The patient has a relatively thin but otherwise healthy cornea
Contact sports or occupational trauma are concerns
Previous surgery makes a flap less desirable
Surface topography-guided treatment is planned
The patient can accept slower recovery
The patient understands the risk of haze and regression

SMILE May Be Considered When:

Myopia or myopic astigmatism is being treated
Avoiding a LASIK flap is important
Faster recovery than PRK is desirable
The cornea is suitable for lenticule extraction
Available treatment customisation meets the patient’s needs

ICL May Be Better Than Both When:

Myopia is very high
Corneal tissue is insufficient
Tomography is unsuitable for corneal laser correction
Preserving central corneal tissue is a priority
Internal eye anatomy is suitable for an implant

ICL avoids corneal ablation but introduces intraocular risks and requires implant-specific long-term monitoring.

Frequently Asked Questions About LASIK vs PRK

Is PRK Safer Than LASIK?

PRK avoids flap-related complications and may preserve more load-bearing stromal tissue.

It has different risks, including more pain, delayed healing and corneal haze.

Neither is universally safer.

Does PRK Give Better Vision Than LASIK?

Final visual acuity is generally similar in suitable patients.

LASIK reaches the final result faster.

Which Has Faster Recovery?

LASIK.

Many patients have functional vision by the next day, while PRK vision commonly takes several weeks to stabilise fully.

Which Is More Painful?

PRK.

Discomfort is usually greatest during the first two to three days while the epithelium heals.

Which Causes Less Dry Eye?

PRK may cause less flap-related corneal denervation, but temporary dryness can occur after either procedure.

Which Is Better for Thin Corneas?

PRK may be suitable when a LASIK flap would leave insufficient load-bearing tissue.

A thin or structurally abnormal cornea may be unsuitable for both.

Which Is Better for Contact Sports?

PRK is often preferred because there is no permanent corneal flap.

Can the LASIK Flap Move Years Later?

Severe trauma can disturb a LASIK flap even years later, although this is rare.

Does PRK Have a Flap?

No.

Is PRK Reversible?

No.

The excimer laser permanently removes corneal tissue.

Is LASIK Reversible?

No.

The flap can be lifted, but the laser-removed tissue cannot be replaced.

Can PRK Cause Scarring?

PRK can cause corneal haze or scarring.

Modern laser profiles, steroids and mitomycin C have reduced this risk substantially.

Why Is a Bandage Contact Lens Used After PRK?

It protects the exposed cornea, reduces discomfort and supports epithelial healing.

How Long Is the Bandage Contact Lens Worn?

It is usually worn until the epithelium has healed adequately, commonly several days.

The surgeon determines when it is safe to remove.

Can I Drive the Day After LASIK?

Some patients may have adequate vision, but driving should resume only after the postoperative examination and when legal visual standards are met.

Can I Drive the Day After PRK?

Usually not.

Vision is commonly blurred during the first several days.

When Can I Return to Work?

Many LASIK patients return to office work within one to three days.

PRK patients may require approximately one week or longer depending on comfort, vision and occupation.

When Can I Exercise?

Light activity can often resume relatively early, but swimming, contact sports and dusty environments should be avoided until the surgeon confirms that healing is adequate.

Can LASIK or PRK Cause Blindness?

Severe permanent visual loss is rare but possible.

Potential causes include:

Infection
Corneal ectasia
Severe haze or scarring
Irregular astigmatism
Other uncommon complications

Can I Still Need Glasses?

Yes.

Glasses may still be needed for:

Residual refractive error
Night driving
Reading after presbyopia develops
Future prescription change

Which Is Easier to Enhance?

LASIK generally has a more straightforward early enhancement pathway.

PRK enhancement is possible but involves another surface-healing period.

Does PRK Last Longer Than LASIK?

Neither procedure universally lasts longer.

Long-term stability depends more on the original prescription, age, corneal healing and natural changes within the eye.

Does Either Procedure Prevent Cataract?

No.

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

Do I Still Need Eye Examinations?

Yes.

Regular examinations remain important for:

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

Key Takeaway

LASIK and PRK are both effective excimer-laser vision correction procedures.

They use similar laser technology to reshape the cornea, but they reach the treatment area differently.

LASIK:

Creates a corneal flap
Causes less early discomfort
Provides faster visual recovery
Has a relatively straightforward enhancement pathway
Carries permanent flap-related risks
May cause more early corneal nerve disruption and dryness

PRK:

Does not create a flap
Preserves more load-bearing anterior stromal tissue
May suit selected thinner corneas
Is often favoured when eye trauma is a concern
Causes more early discomfort
Has slower visual recovery
Carries a specific risk of corneal haze

Final visual acuity, safety and refractive accuracy are generally similar in appropriately selected low-to-moderate myopic patients.

LASIK may be preferred when speed and comfort are priorities.

PRK may be preferred when avoiding a flap or preserving additional stromal tissue is more important than rapid recovery.

Neither procedure:

Is reversible
Eliminates dry-eye risk
Eliminates corneal ectasia risk
Prevents presbyopia
Prevents cataract
Removes the retinal risks associated with high myopia

The safest procedure is the one that best matches the patient’s corneal anatomy, prescription, ocular-surface health, occupation and lifestyle.

References

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Taneri S, et al. Long-Term Outcomes of PRK, LASIK and SMILE. 2022. PMID: 34241701.
Almutairi MN, et al. Clinical Outcomes of LASIK versus PRK: A Meta-analysis. 2025.
US Food and Drug Administration. Patient Information Booklet for LASIK Laser Vision Correction.
US Food and Drug Administration. LASIK Risks, Patient Selection and Postoperative Expectations.
Somani SN, Moshirfar M, Patel BC. Photorefractive Keratectomy. Updated 2025. PMID: 31751077.
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El-Maghraby A, Salah T, Waring GO III, et al. Randomised Bilateral Comparison of LASIK and PRK for Myopia. 1999. PMID: 10080199.
US Food and Drug Administration. LASIK Quality of Life Collaboration Project. 2021.
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Chang YM, et al. Mitomycin C for the Prevention of Corneal Haze in Photorefractive Keratectomy: A Meta-analysis. 2021. PMID: 33326173.
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Arranz-Marquez E, et al. A Critical Overview of the Biological Effects of Mitomycin C in Corneal Refractive Surgery. 2019. PMID: 30859502.
Chang JY, et al. Comparison of Clinical Outcomes of LASIK, TransPRK and SMILE.
Ortega-Usobiaga J, et al. Comparison of Retreatment by Flap Lift and Surface Ablation After LASIK. 2018. PMID: 28651810.
Beerthuizen JJG, et al. Surface Ablation After Laser In Situ Keratomileusis. 2007. PMID: 17662427.
US Food and Drug Administration. FDA-Approved Lasers for PRK and Other Refractive Surgeries.
Ryan DS, et al. A Comparative Analysis of Patient-Reported Outcomes After LASIK, PRK and SMILE. 2025. PMID: 39641610.