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Vision correction
Vision correction & laser eye surgery: Questions and Answers
LASIK, SMILE, SMILE Pro, Femto LASIK, PRK and TransPRK explained, including how each one reshapes the cornea, what each can correct, and the honest comparison between them: which one suits a particular eye is a measurement question, not a preference.
LASIK, SMILE, SMILE Pro, Femto LASIK, PRK and TransPRK explained, including how each one reshapes the cornea, what each can correct, and the honest comparison between them: which one suits a particular eye is a measurement question, not a preference.
General educational information. It does not replace an examination, and it cannot tell you what is happening in your own eyes.
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Vision correction
Every procedure in this section is trying to do the same thing: change the shape of the cornea so that light focuses on the retina instead of in front of it or behind it. They differ in how they reach the tissue they reshape, and that difference is what produces almost every comparison question people ask.
The honest answer to most "which procedure is better" questions is that they are not better or worse in the abstract. They place different demands on the cornea, and your measurements decide which demands your eye can meet.
Vision correction & laser eye surgery questions and answers
Vision correction
LASIK, SMILE, SMILE Pro, Femto LASIK, PRK and TransPRK explained, including how each one reshapes the cornea, what each can correct, and the honest comparison between them: which one suits a particular eye is a measurement question, not a preference.
LASIK is laser vision correction in which a thin flap is created in the surface of the cornea, the tissue underneath is reshaped with an excimer laser, and the flap is laid back into place.
The flap is what distinguishes LASIK from surface treatments such as PRK and from lenticule extraction such as SMILE. It is also why the surface of the eye feels close to normal within a day or so: the outermost layer of the cornea is lifted rather than removed.
Whether it is a reasonable option for a particular eye depends on the measurements taken during an assessment, including corneal thickness, corneal shape and tear film.
LASIK works by removing microscopic amounts of corneal tissue so that the cornea becomes flatter or steeper, which changes where light comes to focus inside the eye.
In short sightedness the cornea focuses light in front of the retina, so the treatment removes tissue from the centre of the cornea to flatten it. In long sightedness the opposite is needed. In astigmatism the goal is to make a cornea that is curved unevenly more regular.
The refractive change is permanent in the sense that the removed tissue does not grow back. How the eye behaves years later is a separate question, which is why stability of your prescription before surgery matters so much.
LASIK is used to correct short sightedness, long sightedness and astigmatism, within limits that depend on your prescription, corneal thickness and corneal shape.
Those limits are not fixed numbers that apply to everyone. A prescription that is well within range for one person may be outside it for another whose cornea is thinner, whose cornea is irregular, or whose tear film is unstable.
LASIK does not correct presbyopia, which is the age-related loss of near focus. That is a separate problem with separate solutions.
The change LASIK makes to the cornea is permanent, but the eye continues to change with age, so vision later in life can differ from the vision you have in the months after surgery.
The tissue removed during treatment does not regrow, so the reshaping itself does not reverse. What changes is everything around it: the natural lens inside the eye stiffens with age, and a small drift in prescription over years is a normal finding.
This is why people who had laser surgery in their thirties may still need reading glasses in their forties and fifties, and why some prescriptions can shift enough to be worth correcting again.
The corneal reshaping does not wear off, so there is no fixed lifespan for the effect. What does change over time is your eye, and the most predictable change is the loss of near focus that begins around the mid-forties.
Reading glasses after forty are usually presbyopia rather than a failure of the surgery. It happens to people who never had laser surgery too.
A small proportion of people experience some regression in their distance prescription over years, which may or may not be enough to want correcting. Ask your clinic what its policy is on retreatment before you commit to anything.
LASIK is an established procedure with a long safety record, but no surgical procedure is risk-free, and the honest version of the question is not whether it is safe in general but whether it is appropriate for your particular eyes.
Serious complications are uncommon, and the more frequent issues are dryness, glare and halos, and imperfect correction. Most of these are temporary or manageable, and some are treatable with further treatment.
The assessment exists to catch the situations that make surgery a poor idea, which is why a clinic that talks you out of treatment after measuring your eyes is behaving well rather than badly.
The risks of LASIK fall into three groups: symptoms such as dry eye, glare and halos; imperfect correction, meaning some prescription remains or too much tissue is removed; and rare complications involving the flap or infection.
Dryness and night vision symptoms are the most commonly reported, and they are also the ones most likely to settle as the surface of the eye heals. Flap-related problems are uncommon but are specific to flap procedures, which is part of why surface treatments remain in use.
Your own risk is not the average risk. Prescription, corneal thickness, tear film and healing all move it, which is what the preoperative assessment is for.
The commonly reported side effects are dry or gritty eyes, halos and glare around lights, light sensitivity and vision that fluctuates during the day, particularly in the first weeks.
These are usually described separately from complications because many of them are expected parts of healing rather than things going wrong. Dryness in particular is common early on, since the surgery temporarily affects the nerves that signal the eye to produce tears.
Halos and glare tend to be most noticeable in low light and often reduce over months. If they persist, they are worth raising with your clinic rather than living with.
LASIK changes the cornea deliberately and permanently, so the question is really whether it can cause harm beyond the intended reshaping. Rarely it can, and the situations worth knowing about are infection, flap problems and a cornea left too thin or too irregular.
A thin or irregular cornea after treatment is the reason corneal measurements are taken so carefully beforehand, and the reason some eyes are declined. In those eyes a different procedure, or no procedure, is the safer answer.
If you have concerns about your own cornea, an examination with corneal imaging is the way to answer them. General information cannot report on your eye.
Total loss of vision from LASIK is not a recognised outcome of the procedure as performed on properly assessed eyes. The complications that are genuinely documented involve the cornea, the flap and the quality of vision rather than the optic nerve or the retina.
That distinction matters because the serious sight-threatening conditions people worry about, such as retinal detachment and glaucoma, are not caused by laser vision correction. They are reasons to have a full eye examination, and they can exist independently of any refractive surgery.
This is one of the cases where a general answer genuinely cannot speak for your eyes. If you have a retinal or optic nerve condition, that belongs in the assessment.
The procedure itself is usually described as pressure rather than pain, because the eye is numbed with drops beforehand. Discomfort afterwards is common and is typically described as grittiness, watering or a burning sensation for some hours.
People report the experience differently, and how much discomfort you feel afterwards cannot be predicted from a page. What matters practically is that your clinic tells you what to expect and what to do if it is worse than expected.
Yes. LASIK is done with the eye numbed by drops, and you are awake and able to follow instructions for the whole procedure. Sedation is not usually needed.
You will be asked to look at a target light while the laser works. If your eye moves, the laser tracking system is designed to follow it or pause, which is a frequent source of worry that clinics are used to addressing before treatment starts.
The laser part of LASIK typically takes only a few minutes per eye, while the whole visit including preparation, checks and settling usually takes considerably longer.
Ask the clinic how long it expects you to be there rather than how long the laser takes, since the answer to the second question is not the useful one if you are arranging time off work or a lift home.
Many people notice a substantial improvement within hours, and most describe vision as usable for ordinary tasks the following day. Vision often continues to sharpen and settle over the following weeks.
Fluctuation is normal in this period: better in the morning, worse in the evening, or varying with dryness. What is not normal is deterioration, and that is a reason to contact the clinic rather than wait.
Most people are back to ordinary daily activities within a day or two, while the eye continues to settle for several weeks and in some cases a few months.
The early phase is about comfort and surface healing, and the later phase is about stability. Vision that is still fluctuating a few weeks in is common and does not usually mean anything has gone wrong.
Your surgeon’s instructions govern what you may and may not do, and they can differ between clinics and between eyes.
Driving depends on whether your vision meets the legal standard for driving and whether you feel able to react safely, so the decision is made per person rather than by the calendar. Most clinics advise arranging not to drive yourself home on the day.
The practical test is your own vision in daylight and at night, plus any discomfort or light sensitivity. If you are unsure, ask the clinic at your first check rather than assuming.
Many people return within a day or two, and screen-heavy work is the main reason to take longer, since early dryness can make prolonged reading uncomfortable.
If your work involves dusty environments, heavy physical activity or driving, the clinic may advise longer. Ask specifically about your own job rather than relying on a general figure.
Light activity is often allowed early, while swimming, contact sports and anything where the eye could be struck are typically deferred until the flap and surface have settled. Your clinic will give you a specific schedule.
Swimming is usually restricted for a period after LASIK because of the infection risk from water, and the same applies to hot tubs, lakes and the sea. Ask your clinic for the period it uses.
Clinics vary, and some distinguish between a treated pool and open water. This is one of the instructions worth getting in writing before surgery rather than guessing afterwards.
Eye makeup is usually avoided for a short period after surgery, mainly to keep particles and bacteria away from the treated surface. The exact timing is the clinic’s call.
It is also worth asking about removing makeup and about facial treatments, since the answer for the eye area can differ from the answer for the rest of the face.
Flying after LASIK is generally permitted, and cabin air dryness is the practical consideration rather than pressure. Ask the clinic how soon it is comfortable with, especially if you are travelling a long distance.
If you are flying to Dubai for treatment, the sequence of assessment, surgery and first check is worth arranging before you book flights, since the first check is what most clinics want before you leave.
Yes, it can, and the usual causes are a small regression in prescription, dry eye affecting the quality of the surface, or the onset of presbyopia. Blur that returns should be assessed rather than assumed to be one of these.
A specific pattern is worth knowing: blur that varies through the day and is worse when the eyes are dry behaves differently from blur that is constant. Describing which one you have is genuinely useful to a clinician.
Some people do, either for a small residual prescription, for reading as presbyopia develops, or because their prescription drifts over the years.
Expecting to never wear glasses again at any point in life is not a realistic aim for most people, and a clinic that frames the result that way is worth being cautious about.
Yes, astigmatism can be treated with LASIK, and the treatment is often combined with correction of short or long sightedness in the same procedure. How much can be corrected depends on your measurements.
Short sightedness is the most commonly treated refractive error with LASIK. Whether your particular prescription is within a range that can be safely corrected depends on your corneal thickness and other measurements.
Long sightedness can be treated with LASIK, but it is a different surgical problem from short sightedness and suitability is assessed more cautiously, particularly at higher prescriptions and in older eyes.
LASIK is generally avoided where the cornea is too thin for the amount of tissue that would need removing, where the cornea is irregular or unstable, where the eye surface is significantly dry, and in a number of medical and medication situations.
Being told you are not suitable for LASIK is not the same as being told nothing can be done. Surface treatments, lenticule extraction or lens-based options may still be appropriate, and sometimes the answer is to treat something else first.
Suitability comes down to a prescription that has been stable, a cornea thick enough and regular enough for the planned correction, a healthy eye surface and no condition that makes healing or measurement unreliable.
Age matters mostly through prescription stability rather than through a fixed cut-off, and general health matters where it affects healing or where medication changes the eye.
All of this is measured, not guessed. Two people with the same prescription in glasses can have very different measurements.
Before LASIK, the assessment usually includes refraction, corneal topography and tomography, measurement of corneal thickness, an assessment of the tear film and ocular surface, eye pressure, and a retinal examination with dilated pupils.
The purpose is not only to decide whether surgery is possible but to decide which procedure and which treatment profile to use. That is why the measurements matter more than the procedure name.
Dilation means your vision stays blurred for some hours, so it is worth planning not to drive yourself home from the assessment.
There is no single cut-off figure, because the limiting factor is usually how much corneal tissue the correction would require rather than the prescription number on its own.
A high prescription in a thick cornea may be treatable while a moderate one in a thin cornea may not. That is why a clinic that quotes a maximum number without measuring your cornea is answering a different question from the one you asked.
Higher prescriptions can sometimes be treated, but the amount of tissue the correction requires rises with the prescription, so corneal thickness becomes the deciding factor more often than the prescription itself.
Where the cornea cannot safely give up that much tissue, alternatives include a surface treatment, lenticule extraction, or a lens-based option such as an implantable lens. Which of those fits is an assessment question.
Yes, a cornea that is too thin for the planned correction is one of the more common reasons LASIK is declined. The measurement that matters is the residual thickness predicted after treatment, not the starting thickness alone.
A thin cornea is not automatically the end of vision correction. Surface treatments remove less tissue than a flap procedure in some situations, and lenticule extraction avoids a flap. Occasionally the finding leads to investigating why the cornea is thin before anything else happens.
Significant dry eye can make LASIK a poor choice, because surgery itself can worsen dryness in the short term and an unstable tear film makes the measurements less reliable and the healing less predictable.
Often the answer is not a refusal but a sequence: treat the ocular surface first, then reassess. A clinic that measures the tear film at all is doing more than one that only refracts you.
Astigmatism does not by itself rule out LASIK, and correcting it is a routine part of many treatments. What matters is the amount and the regularity of the astigmatism, along with the corneal measurements.
Yes, age alone does not rule out LASIK. What changes after forty is that presbyopia is arriving, so the conversation shifts from purely correcting distance vision to deciding how you want to handle near vision as well.
The measurement mix also changes: the tear film tends to be less stable and the natural lens begins to matter more. That is a reason for a thorough assessment, not a reason for automatic exclusion.
Some people can, and some are better served by a different approach, because after fifty the natural lens is often the more significant factor and cataract development starts to enter the plan.
Where a cataract is already forming, treating the lens rather than the cornea may address both problems at once. That is a conversation to have with an ophthalmologist who examines the whole eye rather than only the refraction.
LASIK can remove the need for glasses for distance vision in many people, but no procedure can promise that you will never need glasses again at any point in your life.
Reading glasses as presbyopia develops, glasses for night driving if a small residual prescription remains, and sunglasses for comfort are all ordinary outcomes rather than failures.
Repeat treatment is possible in some eyes but is not automatic, because a second procedure needs enough remaining corneal thickness and a pattern of change that makes sense to treat.
Enhancement is usually considered only after the eye has stabilised, which takes months rather than weeks. Ask about the clinic’s policy, including whether any retreatment is included in the quoted price or charged separately.
If a residual prescription remains after the eye stabilises, the clinic may offer a further treatment, usually a surface procedure or a repeat laser treatment depending on the residual shape and the remaining corneal thickness.
The decision is made from new measurements taken after the eye has settled, not from the original plan. Some residuals are small enough that the clinic advises against another procedure.
Treatment depends on what went wrong. Flap issues are usually repositioned or managed directly, infection is treated with medication, and residual prescriptions may be correctable with further treatment or with glasses.
The most useful question to ask a clinic before surgery is not whether complications happen but what its specific plan is when they do: who you contact, how quickly you are seen, and what is covered.
Femto LASIK is LASIK in which the corneal flap is created with a femtosecond laser instead of a mechanical blade, while the actual reshaping is still done with an excimer laser.
The femtosecond laser works by creating microscopic bubbles at a chosen depth, which allows the flap to be separated along a plane defined in software. The alternative, a microkeratome, cuts the flap mechanically.
The difference is how the flap is made. Femto LASIK uses a laser to create it; other LASIK uses a mechanical instrument. The part of the procedure that corrects your prescription is the same in both.
Whether the difference matters for your eye is something the surgeon should be able to explain for you specifically. "It is newer" is not a clinical reason on its own.
Ultra LASIK is a marketing name rather than a distinct surgical procedure. It generally refers to a flap-based LASIK treatment combined with additional measurement technology, and the specific meaning varies between clinics.
Because the name is not standardised, the useful question is what the clinic actually measures and does differently, and whether it can describe that in terms of your results rather than in terms of equipment branding.
Often not. Many brand names describe a platform, a measurement technology or a marketing package rather than a fundamentally different operation, so it is worth asking what the name changes about your actual treatment.
The answer to look for is concrete: which device, which measurement is used in planning, and what the clinic does differently as a result. Answers that describe the equipment but not your eye are less useful than they sound.
No. SMILE creates no flap. A lenticule is shaped inside the cornea and removed through a small incision, so the surface of the eye is not lifted as it is in LASIK.
The practical consequence is that there is no flap to be displaced or to heal against, which is one of the reasons the procedure is discussed for people in contact sports. The incision still has to heal, and the eye still has to be protected during the early period.
SMILE is generally not used where the prescription falls outside the range the technique can address, where the cornea is unstable or irregular, or where the ocular surface is too dry to measure and heal reliably.
It is also not the usual choice in eyes that have had certain previous corneal surgeries, because the layered structure the technique relies on has already been altered. That is an assessment finding rather than something you can check yourself.
SMILE is used at higher short sighted prescriptions than some older surface techniques, but what can be treated still depends on the cornea rather than on the prescription alone.
The question a clinic should be able to answer is what your predicted corneal thickness would be afterwards, not whether the number on your prescription is under some threshold.
Treating a single eye is possible and is sometimes deliberate, for instance where the two eyes have very different prescriptions or where only one eye is suitable. Much more often both eyes are treated, either on the same day or a short time apart.
Yes, and it is a reasonable question to ask directly. Surgical experience is one of the few things about a clinic that a patient can actually check, alongside licensing and what the quoted price covers.
What makes the answer useful is detail: how many in the last year, how many of your specific procedure on eyes like yours, and who handles follow-up. A vague number is less informative than a specific one.
Short sightedness and myopic astigmatism. Lenticule extraction is established for those two, and long sightedness is not a routine indication on the platforms in general use.
So a SMILE Pro treatment is planned from two numbers: how short sighted you are, and how much astigmatism you have and at what axis. Both are measured during the assessment rather than taken from your glasses prescription, which is a different measurement taken under different conditions.
No. Lenticule extraction uses one laser, a femtosecond laser, to create the lenticule and the small incision; there is no second laser and no excimer step, which is one of the structural differences from a flap procedure.
What this depends on
Which platform the clinic has installed
Whether the clinic performs both types of procedure
It is the opening the surgeon uses to reach and remove the lenticule. The cornea stays intact apart from it, which is what the word flapless describes. The incision is a cut: describing it as keyhole surgery explains where the surgeon works, not how much tissue is involved.
What this depends on
The size of the incision the surgeon plans
How the wound heals in your case
Whether you follow the early aftercare instructions
By asking which laser platform is installed rather than which procedure name the website uses. The two are performed on different generations of the same machine, so the platform identifies the treatment unambiguously in a way the word “Pro” does not.
A clinic that can name its platform, say when it was installed and who services it is answering a question that can be checked. A clinic that answers only in brand language is not, and that difference is worth more than the price difference between two quotes.
What this depends on
The platform name and when it was installed
Which surgeon operates it, and how often
Whether the clinic quotes the two generations at different prices
It is available at fewer clinics, it is not used for long sightedness, enhancement after it is a different procedure from lifting a flap, and the evidence comparing platform generations is still developing. None of those makes it a worse choice; they make it a choice with different trade-offs.
The honest framing is that both SMILE and LASIK have a list of trade-offs and neither list is empty. A clinic that presents only the advantages of the procedure it sells is describing a product, and the assessment is where the difference should appear.
What this depends on
Whether your prescription is inside the treatable range
Whether an enhancement might be needed and how it would be done
Often it is quoted higher, and the reason is the platform rather than the difficulty of the surgery. What matters more than the difference between the two totals is whether each quote covers the same things: the assessment, medication, the follow-up visits and any agreed policy on enhancement.
It can be suitable in some corneas where a flap would remove more tissue than a surgeon is comfortable with, and it is not a way around the problem: every refractive procedure removes tissue, and the amount required is what decides whether an eye is treatable.
What this depends on
The measured corneal thickness and the depth the treatment needs
Because it requires a specific platform, the training that goes with it, and a surgeon who performs it often enough to stay current. A clinic offering many laser procedures will offer LASIK before it offers lenticule extraction.
That is a practical reason rather than a quality judgement in either direction, and it is why availability is not evidence of suitability. The question for your eyes is which procedure your measurements support and who performs it regularly.
What this depends on
Which clinic near you has the platform
How much of the surgeon’s practice is lenticule extraction
Whether you are willing to travel for a specific surgeon
Experienced in this procedure specifically, which is a different question from how long they have been an ophthalmologist. Lenticule extraction has a learning curve that is not identical to flap surgery, so the relevant number is how many of these they perform and how often.
What this depends on
The volume of lenticule procedures the surgeon performs
Whether they can describe how they handle a difficult case
Whether the person who assesses you is the person who operates
Yes. During the laser step the eye is held against a curved interface, which is the pressure sensation most patients describe, and the platform tracks the eye while it works. The surgeon pauses or stops if the eye cannot be held in position.
Knowing that part of the sequence is expected is the single most useful thing for a nervous patient: a pressure sensation and temporarily grey or darkened vision during the laser step are reported commonly, and both are predictable rather than a sign that something has gone wrong.
What this depends on
Your ability to keep looking at the fixation light
It is discarded as surgical tissue after removal. Because the lenticule is a shaped piece of cornea, researchers have explored reusing donated lenticules for other purposes, but that is experimental work and not part of routine care.
What this depends on
What the clinic’s own policy is
Whether the tissue is retained for any research purpose
Whether you are asked to consent to anything of the kind
Usually not. A cornea that has already had a flap procedure has less tissue and a different structure, and lenticule extraction assumes an intact cornea. Where a residual prescription after LASIK is treated, a surface treatment or a flap lift is the more usual route.
What this depends on
How much tissue was removed the first time
The size and direction of the residual prescription
Whether the original flap and its measurements are documented
PRK is laser vision correction in which the thin outer layer of the cornea is removed, the surface underneath is reshaped with an excimer laser, and the outer layer grows back over the following days.
It is the oldest of the modern surface procedures and is still used because it needs no flap and removes less tissue than a flap procedure for the same correction. The trade-off is a slower and less comfortable first week.
TransPRK is a version of PRK in which the outer layer of the cornea is removed by the excimer laser itself rather than by a separate step, so the whole treatment happens in one continuous laser pass.
Removing one instrument from the sequence reduces handling of the eye surface, which is the claim made for it. The recovery profile is essentially that of PRK: a slower start than a flap or lenticule procedure.
PRK works by removing the surface layer of the cornea and then removing corneal tissue in a pattern calculated from your measurements, which changes where light comes to focus.
Because there is no flap, the structural change is confined to the front of the cornea. That is why it remains an option in some eyes where a flap would be undesirable.
The procedure itself is not painful because the eye is numbed. The first few days afterwards are commonly described as uncomfortable, with grittiness, watering and light sensitivity while the surface layer regrows.
This early period is the main practical difference from flap and lenticule procedures, and it is the reason people planning around work or travel should factor it in.
PRK recovery is longer because the outer layer of the cornea has to regrow, and vision stays soft while it does. Flap and lenticule procedures leave that layer intact, so the surface settles sooner.
PRK is often considered where the cornea is thin, where the surface is irregular, or where a flap carries a specific risk, such as in people whose work or sport involves a high chance of eye trauma.
It is also sometimes chosen simply because a surgeon judges the surface outcome more predictable for that particular cornea. That is a clinical judgement made from imaging, not from preference.
PRK is one of the options considered when the cornea is thin, because creating a flap and the tissue it requires is avoided. Whether it is appropriate still depends on the predicted remaining thickness for your correction.
The risks of PRK overlap with those of other laser procedures: dryness, glare and halos, and imperfect correction. It also has a specific risk of haze, which is a healing response in the surface tissue.
Haze is one reason surface treatments are often paired with medication during healing, and one reason the aftercare instructions matter in the first weeks.
Blur immediately after PRK is expected, and it can take longer to settle than after flap procedures. Blur that appears or worsens months later is a different matter and should be assessed.
Returning to work after PRK depends on how quickly the surface settles and on what your work involves. It is usually longer than after a flap or lenticule procedure.
Screen work is the awkward case: it is not physically demanding, but early surface discomfort and light sensitivity can make it genuinely hard. Ask the clinic how it usually advises people in your job.
Driving after PRK waits on your vision reaching the legal standard and on the discomfort being gone, which usually takes longer than after LASIK or SMILE. Arrange not to drive yourself home from the procedure.
Light exercise is often permitted early, while swimming and anything risking a knock to the eye are deferred until the surface has healed. Follow the schedule your clinic gives you, since it is tailored to your healing.
LASEK is a surface treatment in which the thin outer layer of the cornea is loosened with alcohol and folded back, the excimer laser is applied underneath, and the layer is replaced. It sits between PRK, where that layer is removed, and LASIK, where a thicker flap is created.
The differences between these surface variants matter less than the thing they share: the treatment is applied to the surface, so the eye has to regrow that layer, which is why the first few days are less comfortable than after a flap or lenticule procedure.
Epi-LASIK is a surface treatment in which a mechanical blade separates the outer corneal layer before the laser is applied, instead of using alcohol or the laser itself. The clinical aim is the same as PRK: reshape the surface and leave no flap.
Branded names for surface techniques multiply because each device maker named its own version of the same idea. When a clinic quotes a name you have not heard, the useful questions are which layer is being removed or replaced, and whether the treatment is on the surface or under a flap.
Corneal haze is a recognised surface-treatment finding, and modern technique and aftercare have made it less common than it was in earlier decades. It is more likely with higher prescriptions and with deeper treatment, and it is one of the reasons surface treatment is planned around your measurements.
Haze is a change in the clarity of the surface as it heals, not a scar that cannot be managed, and clinics use preventive medication after surface treatment for that reason. If you are considering PRK for a high prescription, this is a specific question worth asking.
What this depends on
The size of the prescription being treated
The depth of tissue removed
The post-operative medication regime and your adherence to it
Vision usually improves over the first week as the surface layer regrows, and then continues to settle over weeks to months. It is normal for the two eyes to recover at different speeds, and for vision to fluctuate while they do.
The reason clinics are specific about the first days after surface treatment is that the eye is uncomfortable while the surface heals, and this is when people are most likely to wonder whether something is wrong. It is also the period when the eye is most vulnerable to infection, which is why the instructions are strict.
A further surface treatment is possible in selected cases, provided there is enough corneal tissue left and the reason for the residual prescription is understood. It is not automatically offered, and the decision rests on the same measurements that decided the first treatment.
What this depends on
How much corneal tissue remains
Whether the residual prescription has stabilised
Whether the first result was limited by healing or by planning
Yes. Surface treatment can correct astigmatism as well as short sightedness and long sightedness, and the ablation is shaped to the amount and axis of your astigmatism.
Both are surface treatments. In PRK the outer corneal layer is removed first and the excimer laser then reshapes the tissue underneath. In TransPRK, the laser itself removes that layer and performs the reshaping in one continuous step, without alcohol or a blade.
Whether the single-step version produces a different outcome is a question clinicians still answer differently, and a clinic’s preference is usually about the platform installed and how the surgeon was trained. What both share, and what matters most to a patient, is the slower first week compared with a flap or lenticule procedure.
What this depends on
Which platform the clinic has
Which technique the surgeon performs regularly
Whether either approach is unsuitable for your cornea
Swimming and other water exposure are restricted until the surface of the eye has healed and your surgeon says so. The restriction is usually longer after surface treatment than after a flap or lenticule procedure, because the outer layer is regrowing.
What this depends on
How quickly your surface heals
Pool water versus sea or open water
What your own surgeon instructs at the follow-up visit
Surface treatment is unsuitable where the cornea is unstable or too thin for the planned correction, where there is active surface disease or significant dry eye, and where the healing response is expected to be unpredictable. It is also a poor fit for someone who cannot follow a strict early aftercare routine.
What this depends on
Corneal thickness and topography
The state of the ocular surface
Your ability to attend follow-up visits in the first days
Surface treatment is one of the ways a residual prescription after LASIK is corrected, because it does not require lifting the original flap. The decision depends on how much tissue remains and on the reason the residual is there.
This is one of the practical differences between the procedures that is easy to miss when choosing: after a flap procedure, enhancement can often be done by lifting the existing flap, and after a surface or lenticule procedure the options are different.
It can, within the limits the cornea allows, and surface treatment is sometimes chosen precisely because it conserves tissue compared with creating a flap. Higher prescriptions remove more tissue wherever the treatment is applied, so the measurement matters more than the technique.
What this depends on
Corneal thickness and the depth the treatment requires
Whether a lens-based option would be safer
The haze risk associated with deeper surface treatment
Surface ablation is the family name for treatments that reshape the cornea from the outside rather than by lifting a flap or removing a lenticule from inside. PRK, LASEK, epi-LASIK and TransPRK are all surface ablation.
Grouping them is useful when reading a comparison: the trade-off a reader is choosing between is really surface versus flap versus lenticule, and the marketing names within each group describe technique details rather than different optical outcomes.
SMILE reshapes the cornea and removes tissue; an implantable lens leaves the cornea intact and adds a lens inside the eye. They are used in different situations, most often at high prescriptions where too much corneal tissue would be needed.
The two are not competing for the same eye in most cases. Where a cornea cannot give up the tissue a laser procedure needs, a lens-based option may be the reasonable route, and where the eye is otherwise healthy with a moderate prescription, a corneal procedure usually is.
PRK removes the cornea’s outer layer and lets it regrow, while LASIK lifts a flap and replaces it. PRK involves no flap but a slower, more uncomfortable first few days.
The clinical reasons to prefer one over the other usually relate to corneal thickness, corneal surface health and the risk of eye trauma in your occupation or sport. Comfort and speed favour LASIK; the absence of a flap favours PRK in some situations.
PRK removes the outer corneal layer and reshapes the surface, while SMILE removes a shaped piece of tissue from inside the cornea through a small incision. Both avoid a flap, and they differ mainly in recovery speed and in how the eye surface is left.
The choice is made from your measurements rather than from your preference or from a general claim about which is better. Corneal thickness, corneal shape, prescription, tear film and the planned correction all feed into it.
A useful way to test whether the recommendation is real is to ask which of your measurements drove it. If the answer is a measurement you can see on your own report, the recommendation is specific to you.
The difference is the access route. LASIK lifts a flap and reshapes beneath it; SMILE shapes a lenticule inside the cornea and removes it through a small incision. The rest of the treatment plan is built the same way, from your measurements.
Both use a femtosecond laser, but Femto LASIK uses it to create a flap that is then lifted, while SMILE uses it to create an incision and a lenticule. The excimer reshaping step that follows is where the rest of the difference lies.
They are two different techniques, not two versions of one. SMILE Pro removes a lenticule with no flap; Femto LASIK creates a laser flap and reshapes the cornea beneath it with a separate excimer laser.
Both are modern platforms, and a clinic that presents one as simply better than the other is compressing a clinical decision into a marketing one. The relevant question is which technique your cornea is better suited to.
Flap and lenticule procedures generally settle more quickly than surface treatments, because the outer layer of the cornea is left intact. Beyond that the differences between individual procedures are smaller than the differences between individual patients.
Healing speed varies with the eye, the prescription and the surface health, so recovery times quoted in comparison tables are typical ranges rather than predictions about you.
Surface treatments such as PRK are usually the most uncomfortable in the first few days, because the outer layer of the cornea regrows. Flap and lenticule procedures are generally reported as more comfortable early on.
Reports differ between people, and this is one of the areas where individual experience varies more than procedure averages do.
All of the corneal procedures can affect the tear film, and the honest answer is that dryness is assessed and treated before any of them is planned. Where dryness is significant, a lens-based option may be discussed instead.
There is research comparing dryness between procedures, but it describes group averages rather than your eye. The useful part of the answer is the sequence: measure the surface, treat it if needed, then reassess.
The limiting factor is how much corneal tissue the correction requires, not the procedure name. Techniques that remove less tissue, and lens-based options, come into their own as prescriptions rise.
LASIK, SMILE and PRK can all treat astigmatism within limits set by your measurements. Larger amounts, or astigmatism from an irregular corneal surface, may point towards a different option entirely.
People who play sport often end up discussing procedures without a flap, on the reasoning that there is nothing to displace if the eye is struck. That is a reasonable consideration, and it is still assessed against your measurements rather than assumed.
Protective eyewear during the healing period remains part of the advice regardless of procedure, and your clinic will tell you for how long.
Contact sports are one of the situations where a surgeon may steer away from a flap procedure, because a flap can in principle be displaced by trauma even years later. Flap-free options are often discussed instead.
Balanced against that, recovery and comfort usually favour the flap procedure. Which way the balance falls depends on how much you play, at what level, and what your cornea looks like.
Where the cornea is thin, procedures that remove less tissue or need no flap are more likely to be considered, and a lens-based option may be raised where even those would take too much. The deciding measurement is the predicted remaining thickness.
Treat the dryness first, then reassess. Dryness is a treatable finding in many people, and what is available to you afterwards may be different from what it looks like now.
If the dryness does not respond, that changes the conversation towards options that do not alter the corneal surface, and it is a conversation to have with the clinician who measured you rather than from a comparison table.
For a well-selected eye, modern procedures produce broadly comparable outcomes. Differences show up more in which eyes each technique suits than in a general ranking of visual results.
This is also why outcome figures quoted by clinics need reading carefully: the population a clinic operates on, and the criteria it counts as success, affect the number at least as much as the technique does.
You can and should express a preference, and the surgeon should explain whether your measurements support it. What should not happen is a procedure being performed because it was requested when the cornea suggests a different one.
The useful version of the conversation is: here are my measurements, here is what you recommend, and here is why. A clinic that cannot walk you through that is worth pausing over.
Read it as a list of the factors that differ, not as a scoreboard. Every procedure in a comparison table is the best available answer for some eyes, and the table is telling you which factors to ask about.
The rows that matter most in practice are usually the ones about corneal tissue, dry eye and the recovery period, because those are where your own measurements change the answer.
All laser vision correction procedures remove or reshape corneal tissue to change the eye’s focusing power, and they differ mainly in how the laser reaches the tissue it needs to reshape.
Two lasers are usually involved in modern treatment. A femtosecond laser creates the access route, whether that is a flap in LASIK or the incision and lenticule in SMILE. An excimer laser then removes tissue in a precisely controlled pattern designed from your own measurements.
Because every procedure ends in the same place, the differences between them are mostly about the cornea’s structure afterwards and how the eye heals in the first days and weeks.
Refractive surgery is any procedure that changes the eye’s focusing power in order to reduce dependence on glasses or contact lenses, and it includes corneal laser procedures as well as lens-based operations.
Corneal procedures change the shape of the front surface of the eye. Lens-based procedures replace or supplement the natural lens. They are used in different situations and are not interchangeable.
The numbers, measured in dioptres, describe how much and in what direction light needs to be bent to focus on your retina. A minus value means short sightedness, a plus value means long sightedness, and a cylinder value describes astigmatism.
The axis number alongside the cylinder describes the direction of the astigmatism, and two different sets of readings from two different optometrists can both be correct, because refraction depends partly on how you respond during the test.
Neither is better in general. Glasses are reversible and low risk; surgery is permanent and convenient for people it suits. Which one is the better choice depends on your eyes, your prescription and how much the dependence bothers you.
The reversal point is the one worth weighing honestly. If you do not like a pair of glasses, you change them. If you do not like the result of surgery, options are more limited.
The main groups are glasses, contact lenses, corneal laser procedures such as LASIK, SMILE and PRK, implantable lenses, and lens replacement where a cataract or presbyopia is the dominant problem.
Each group solves the same focusing problem in a different way, and each has a set of situations where it is the sensible choice and situations where it is not. Reading about all of them before an assessment is more useful than deciding in advance which one you want.
Laser vision correction is performed by ophthalmologists with additional refractive surgical training, working in a licensed facility. In Dubai, the facility and the practitioner are licensed by the health authority.
Checking a specific surgeon means checking their licence and their scope of practice with the authority that issued it, rather than relying on a clinic page. The UAE section of this knowledge base explains how that works.
These answers describe what is generally true. They are not a diagnosis and they cannot say
whether a treatment is suitable for you, because suitability depends on measurements taken during
an examination. Only a qualified ophthalmologist who has examined you can decide.
A continuously updated clinical reference chapter covering SMILE indications, technique, outcomes and complications, written for clinicians.
Used for How the lenticule is created and removed; Indications and contraindications; Complication categories; Corneal biomechanics compared with flap-based surgery.
A single comparative study of SMILE performed on the newer and older generations of the ZEISS platform. A single study, not a pooled analysis.
Used for The SMILE vs SMILE pro section, explicitly labelled as single-study evidence.
Link checked 22 September 2026
Dry Eyes After SMILE Peer-reviewed literature Peer-reviewed literature (via PubMed Central)
A review of ocular surface changes after SMILE, including how dry-eye signs and symptoms are measured and how they change over the first postoperative months.
Used for Explaining why dry eye is a key preoperative consideration.
The manufacturer’s own product page for the femtosecond laser platform used for SMILE pro.
Used for What describes the technology behind SMILE pro; The distinction between SMILE and SMILE pro; Claimed workflow features such as automated centration.
Hospital patient education describing what happens before, during and after small incision lenticule extraction. It describes the typical course of treatment rather than predicting any individual outcome.
Used for What SMILE involves, for readers arriving before the procedure pages; What the period immediately after treatment is typically like.