SMILE Eye Surgery

Introduction

If you are considering laser vision correction, you have probably come across SMILE eye surgery as a newer alternative to LASIK. SMILE stands for Small Incision Lenticule Extraction. It is a refractive laser procedure that reshapes the cornea — the clear front surface of the eye — to reduce or remove the need for glasses or contact lenses in people with nearsightedness, with or without astigmatism.

SMILE is sometimes described as “flapless” laser eye surgery because, unlike LASIK, it does not involve creating a hinged corneal flap. Instead, a small disc of tissue is shaped inside the cornea and removed through a tiny opening of just a few millimetres.

This guide is written for readers who are weighing up SMILE as a vision-correction option, or who have been offered SMILE by an ophthalmologist and want to understand what to expect. It explains how the procedure works, who is and is not a suitable candidate, the alternatives, the typical recovery, and the risks involved. The aim is not to tell you which procedure is right for you — that is a clinical decision made with your eye surgeon after detailed testing — but to give you the background you need for an informed conversation.

What Is SMILE Eye Surgery?

SMILE is a type of refractive surgery. Refractive surgery is any procedure that changes the focusing power of the eye to correct blurred vision caused by the shape of the eye. In most people, blurry distance vision is due to myopia (nearsightedness), where the eye is slightly too long or the cornea is too curved, so light focuses in front of the retina instead of on it. Astigmatism happens when the cornea is shaped more like a rugby ball than a football, so light focuses unevenly.

SMILE uses a single laser, called a femtosecond laser, to create a thin, lens-shaped piece of tissue (a lenticule) within the body of the cornea. The surgeon then removes the lenticule through a small incision — typically between 2 and 4 millimetres — on the corneal surface. Removing this tissue flattens or reshapes the cornea so that light focuses correctly on the retina.

SMILE was first performed in the late 2000s and has been approved by regulatory bodies in many countries, including the US Food and Drug Administration, for the correction of myopia and, more recently, myopic astigmatism within defined ranges. It is now performed widely in India and across the world as one of the established options for refractive surgery, alongside LASIK and PRK.

How SMILE Differs from LASIK

The key difference is the absence of a corneal flap. In LASIK, the surgeon creates a circular flap across most of the corneal surface, lifts it, reshapes the tissue underneath with an excimer laser, and replaces the flap. In SMILE, no flap is made; the shaped tissue is extracted through a small side opening. This has several practical consequences:

• The surface incision is much smaller in SMILE.
• More of the corneal nerves on the surface are preserved, which may reduce the severity and duration of post-operative dry eye.
• The biomechanical stability of the cornea is, in some studies, better preserved because the front layers remain largely intact.
• SMILE typically uses only one laser, whereas LASIK uses two (a femtosecond laser to make the flap and an excimer laser to reshape the tissue).

These differences do not automatically make SMILE “better” for every patient. LASIK has decades of follow-up data, can correct a wider range of prescriptions (including farsightedness), and is often easier to enhance later if needed. The choice between procedures depends on your prescription, corneal anatomy, lifestyle, and surgeon's assessment.

Why Is SMILE Eye Surgery Performed?

SMILE is performed to reduce or eliminate dependence on glasses or contact lenses for distance vision. It is currently approved and routinely used for:

• Myopia (nearsightedness), typically in the low to high range covered by current laser platforms.
• Myopic astigmatism, where nearsightedness is combined with astigmatism, within approved limits.

SMILE is not currently used to correct hyperopia (farsightedness) outside of clinical trial settings, and it does not treat presbyopia — the age-related loss of near focus that usually begins in the 40s and eventually leads to needing reading glasses regardless of laser surgery.

Refractive surgery, including SMILE, is generally considered elective. People choose it for reasons such as:

• Difficulty tolerating contact lenses, including chronic dry eye, allergies, or recurrent infections.
• Occupational requirements where glasses or lenses are impractical, such as for some athletes, defence personnel, swimmers, and divers.
• A personal preference for not depending on corrective eyewear day to day.

Who Is a Candidate?

• Age 18 or older. Refractive surgery is not performed on children or adolescents because the eye is still changing. Most surgeons prefer patients to be in their early 20s or older.
• A stable prescription for at least 12 months. If your glasses prescription has been changing recently, surgery is usually deferred.
• A prescription within the treatable range for SMILE. The exact limits depend on the laser platform and country-specific approvals, but very high myopia or strong astigmatism beyond these limits may be better treated with other procedures or with an implantable lens.
• A healthy cornea of adequate thickness. The surgeon must be able to remove the lenticule while leaving enough corneal tissue behind to keep the eye structurally safe.
• No keratoconus or other corneal disease. Keratoconus is a condition where the cornea progressively thins and bulges. Laser surgery can worsen it and is contraindicated.
• Reasonable tear film and ocular surface health. Severe dry eye may need treatment first and may influence which procedure is chosen.
• Realistic expectations. The aim is independence from glasses for most everyday tasks, not perfect vision in every situation forever.

When SMILE May Not Be Suitable

SMILE may not be appropriate, or may be deferred, in the following situations:

• Pregnancy or breastfeeding, which can temporarily change the prescription.
• Uncontrolled autoimmune or connective tissue disease, which can affect corneal healing.
• Active eye infection, inflammation, or uncontrolled glaucoma.
• Significant cataract, where lens-based surgery is more appropriate.
• Very thin corneas or borderline corneal topography findings suggestive of early ectatic disease.
• Farsightedness as the main refractive error (SMILE is not currently used for this in routine practice).

The preoperative assessment is designed to identify these issues before any surgical decision is made.

Alternatives to SMILE

SMILE is one of several established options for correcting refractive errors. The main alternatives are described below. Which is most appropriate depends on your prescription, corneal thickness and shape, lifestyle, and the surgeon's professional judgement.

LASIK (Laser-Assisted In Situ Keratomileusis)

LASIK is the most widely performed refractive surgery worldwide. A thin corneal flap is created, lifted, and an excimer laser reshapes the underlying tissue before the flap is replaced. LASIK can correct nearsightedness, farsightedness, and astigmatism. Visual recovery is usually very fast, often within a day. The main considerations are the flap itself, which carries a small long-term risk of dislocation with eye trauma, and a higher rate of temporary dry eye compared with SMILE in some studies.

PRK (Photorefractive Keratectomy)

PRK was the first widely used laser refractive procedure and is still actively performed. No flap is made; instead, the surface layer of the cornea (the epithelium) is removed, and the excimer laser reshapes the surface directly. The epithelium then regrows over a few days. PRK is often preferred when the cornea is too thin for LASIK or SMILE, or when there are concerns about flap safety — for example, in people involved in contact sports or some occupations. Recovery is slower and more uncomfortable in the first week than with LASIK or SMILE, but the long-term outcomes are well established.

Implantable Collamer Lens (ICL)

For people whose prescription is too high for laser surgery, whose corneas are too thin, or who are not laser candidates for other reasons, an implantable collamer lens may be considered. This is a soft lens placed inside the eye, in front of the natural lens, without removing any corneal tissue. ICL is reversible in the sense that the lens can be removed, but it is an intraocular procedure with a different risk profile from laser surgery.

Glasses and Contact Lenses

Continuing with glasses or contact lenses is always a valid option. Modern contact lenses, including daily disposables and toric lenses for astigmatism, offer good vision for most people and avoid any surgical risk. Some people who have tried surgery still choose to wear glasses for certain situations. Choosing not to have surgery is not failure — it is simply one of the available paths.

Preparing for SMILE Eye Surgery

Once you and your surgeon have agreed that SMILE is appropriate, preparation involves both an assessment phase and a short period of practical preparation in the days before surgery.

The Preoperative Assessment

A thorough assessment is essential and typically includes:

• Refraction testing to confirm your exact prescription.
• Corneal topography and tomography, which produce detailed maps of the front and back surfaces of the cornea to detect any irregularities such as early keratoconus.
• Pachymetry to measure corneal thickness.
• Pupil size measurement, especially in dim light, which can influence the risk of night-time glare.
• Tear film assessment for dry eye.
• Intraocular pressure measurement and a dilated examination of the retina to rule out other eye conditions.

The surgeon uses these results to decide whether SMILE is suitable and to plan the exact laser settings for your eye.

In the Days Before Surgery

Specific instructions vary between clinics, but common guidance includes:

• Stop wearing soft contact lenses for at least one to two weeks before assessment and surgery, and rigid gas-permeable lenses for longer, because contact lenses temporarily change the shape of the cornea.
• Avoid eye make-up, perfumes, and lotions around the eyes on the day of surgery.
• Arrange transport home, as your vision will be blurry immediately after the procedure.
• Eat a normal meal before the procedure; SMILE is done under topical anaesthesia (eye drops), not general anaesthesia, so fasting is not usually required.
• Plan a few days off from work and screen-heavy activity.

If you take regular medication or have any general health condition, tell the clinic in advance so they can give specific guidance.

What Happens During SMILE Eye Surgery

Step 1: Anaesthesia and Positioning

You lie on a reclining bed under the laser. Numbing eye drops are placed in the eye being treated. No injections are needed. A small device gently holds the eyelids open so you do not need to worry about blinking. Many patients are offered a mild oral sedative if they feel anxious, but you remain awake and aware throughout.

Step 2: Docking and Laser Creation of the Lenticule

The surgeon brings the laser into contact with the surface of your eye using a soft suction interface. You will feel pressure and your vision will dim briefly. The femtosecond laser then creates two precise planes inside the cornea, defining the lens-shaped piece of tissue (the lenticule) that needs to be removed, as well as the small side incision through which it will be extracted. This step takes less than half a minute per eye.

Step 3: Removal of the Lenticule

Once the laser is complete and the suction is released, the surgeon uses fine instruments to enter through the small incision, separate the lenticule from the surrounding tissue, and gently remove it in one piece. As the lenticule is removed, the cornea naturally settles into its new shape. The opening is small enough that no stitches are needed.

Step 4: Second Eye and Immediate Aftercare

If both eyes are being treated on the same day, which is common, the process is repeated for the second eye. After the procedure, you rest briefly in a recovery area. The surgeon checks the eye at a slit lamp and prescribes eye drops to use over the following weeks. You can usually leave the clinic within an hour.

Most people describe SMILE as painless during the procedure itself. Awareness of pressure, light, and brief darkness during the laser step is normal. In the hours after surgery, mild discomfort, watering, and a gritty sensation are common as the anaesthetic wears off.

Recovery and Healing

The First 24 to 48 Hours

Immediately after surgery, vision is usually hazy, like looking through a steamy window. The eyes may water, feel scratchy, and be sensitive to light. Most people are advised to go straight home, keep the eyes closed, and rest or nap for several hours. Mild oral pain relief is usually enough if any discomfort is felt. By the next morning, vision has often improved noticeably, although it may still fluctuate.

The First Week

Useful vision typically returns within the first few days. Many people return to office work, reading, and screen use within two to three days, although the eyes may tire more quickly than usual. Eye drops — usually an antibiotic and an anti-inflammatory, sometimes a lubricant — are used several times a day. Eye protection at night (shields or goggles) is often advised for the first week to prevent accidental rubbing during sleep.

Weeks Two to Four

Vision continues to stabilise. Some fluctuation between mornings and evenings is normal. Lubricating drops are usually continued for several weeks because dry eye is common during this period, though typically milder and shorter than after LASIK.

Months One to Three

Most people reach their final, stable vision within one to three months. Night-time glare, halos around lights, or starbursts — if present — usually settle during this period. By three months, the cornea has largely healed and the prescription is generally stable.

Aftercare Guidance

Specific instructions are given by your surgeon, but typical advice includes:

• Do not rub your eyes for at least the first few weeks.
• Avoid swimming pools, hot tubs, and natural water for around two to four weeks.
• Avoid eye make-up for at least one to two weeks.
• Avoid contact sports and dusty environments in the first weeks; wear protective eyewear when returning to them.
• Use prescribed eye drops exactly as directed, even if the eye feels fine.
• Attend all scheduled follow-up appointments, typically the day after surgery, then at one week, one month, and three months.

Risks and Complications

SMILE has a strong safety record, but no surgery is risk-free. Understanding the potential complications — and how common they are — is part of giving informed consent. Specific rates vary across studies and surgeons.

Common, Usually Temporary Issues

• Dry eye. Most people experience some dryness in the weeks after surgery. This usually improves as corneal nerves recover and is typically milder than after LASIK. Lubricating drops help.
• Visual fluctuation during the first weeks, especially in the evenings or with prolonged screen use.
• Glare and halos around lights at night, particularly in the first few months. These usually fade.
• Mild discomfort, watering, and light sensitivity in the first 24 to 48 hours.

Less Common Complications

• Under-correction or over-correction, where the final prescription is not quite at the target. Small residual errors may be left as they are or treated later, often with a PRK enhancement.
• Difficulty extracting the lenticule, which is more likely in very early experience and at low prescriptions. Surgeons trained in SMILE have specific techniques to manage this.
• Retained lenticule fragments, which are rare but may need a second procedure.
• Inflammation inside the corneal pocket, which is uncommon and usually responds to steroid drops.

Rare but Serious Complications

• Infection (keratitis), which is very uncommon after SMILE but, if it occurs, requires urgent treatment with antibiotic drops.
• Corneal ectasia, a progressive thinning and bulging of the cornea similar to keratoconus. This is rare and is the main reason that thorough preoperative corneal screening is essential.
• Persistent dry eye or persistent visual symptoms, where dryness, glare, or starbursts continue beyond the usual recovery period. These are uncommon but should always be discussed before surgery.

If you develop sudden eye pain, marked redness, sticky discharge, sudden drop in vision, or significant light sensitivity in the weeks after surgery, contact your surgeon promptly rather than waiting for the next scheduled visit.

Life After SMILE Eye Surgery

Most people who have SMILE achieve vision close to 20/20 without glasses for distance and are able to drive, work, and play sport without correction. Studies of SMILE outcomes show that the large majority of patients within the approved prescription range are satisfied with their vision in the long term, with results that remain stable over many years of follow-up.

Several realistic points are worth keeping in mind:

• SMILE corrects the prescription you have at the time of surgery. It does not stop the eye from changing later in life. A small drift in prescription over many years can occur in some people.
• Reading vision still ages. From the 40s onwards, almost everyone develops presbyopia and will eventually need reading glasses or a reading add, regardless of having had laser surgery for distance.
• Cataract surgery later in life is still possible. Having had SMILE does not prevent cataract surgery if it becomes needed in older age, although the eye measurements taken before SMILE may be useful for choosing an intraocular lens later.
• Routine eye care continues. Annual or every-two-year eye examinations are recommended to monitor general eye health, including the retina and the optic nerve, both of which are unaffected by SMILE.

If a small residual prescription remains and bothers you, an enhancement procedure may be possible. With SMILE, enhancements are often performed using surface PRK on the already-treated eye, rather than repeating SMILE. Your surgeon will discuss the options if this situation arises.

SMILE in Younger and Older Adults

SMILE is not performed on children or adolescents, because the eye is still growing and the prescription is still changing. The minimum age is 18, and most surgeons prefer the prescription to have been stable for at least a year before considering surgery, which often means waiting until the early 20s.

In older adults, SMILE remains an option for distance correction as long as the cornea is healthy and there is no significant cataract. From around the mid-40s, presbyopia means that reading glasses will eventually be needed even after successful SMILE. From the late 50s and 60s onwards, if a cataract is developing, lens-based surgery rather than laser surgery is often the more appropriate route, because cataract surgery itself can correct refractive error using an intraocular lens.

Choosing a Surgeon and Centre

SMILE is a technique-sensitive procedure, and outcomes depend significantly on the experience of the surgeon and the quality of the equipment. When evaluating a refractive surgery service, the following are reasonable things to look for:

• An ophthalmologist with specific training and ongoing experience in refractive surgery, including SMILE.
• Access to up-to-date femtosecond laser technology approved for SMILE.
• A thorough preoperative workup that includes corneal topography and tomography, not just a basic refraction.
• Willingness to advise against surgery if you are not a good candidate, and to discuss alternatives such as LASIK, PRK, or ICL openly.
• A clear plan for follow-up appointments and for handling enhancements or complications.
• Time to ask questions and a clear, written consent process.

Meeting more than one surgeon before deciding is reasonable, particularly if you have an unusual prescription, a borderline corneal scan, or any concerns about candidacy.

Frequently Asked Questions

Is SMILE eye surgery painful?

The procedure itself is not painful because the eye is fully numbed with anaesthetic drops. You may feel pressure during the docking step and brief darkening of vision while the laser is working. In the hours after surgery, mild discomfort, watering, and light sensitivity are common and usually settle by the next day.

How long does SMILE take?

The laser part of the procedure takes less than a minute per eye. The total time in the laser suite, including preparation and positioning, is usually 20 to 30 minutes for both eyes.

When can I return to work after SMILE?

Many people return to office or screen-based work within two to three days. Jobs involving dust, water, or contact sport may require a longer break. Your surgeon will give specific advice based on your work environment.

Is SMILE safer than LASIK?

Both procedures have strong safety records. SMILE avoids creating a corneal flap, which removes the small long-term risk of flap displacement and may reduce dry eye symptoms. LASIK has decades of follow-up data and can treat a wider range of prescriptions, including farsightedness. The safer choice for an individual depends on their corneal anatomy, prescription, and lifestyle. This is a clinical decision made with your surgeon.

Will I still need glasses after SMILE?

The aim of SMILE is independence from glasses for distance vision in everyday situations, and most people achieve this. Some may still use glasses occasionally, for example for night driving if mild residual error is present. Reading glasses are likely to be needed later in life because of age-related presbyopia, which SMILE does not prevent.

Can SMILE be reversed?

No. Because tissue is removed from inside the cornea, SMILE is not reversible. However, if some residual prescription remains, an enhancement procedure such as PRK can often be performed later.

How long do the results of SMILE last?

The corneal reshaping itself is permanent. Studies with several years of follow-up show stable vision in the large majority of patients. However, the eye continues to age naturally, and presbyopia and other age-related conditions still develop on the normal timeline.

Can SMILE be done on both eyes the same day?

Yes. Treating both eyes on the same day is the usual practice and is convenient for recovery. If there is any specific clinical reason to stagger the eyes, the surgeon will discuss it.

Can I have SMILE if I have astigmatism?

SMILE is approved for myopic astigmatism within defined limits. Whether your astigmatism is within the treatable range depends on its size and direction, and on the laser platform being used. The preoperative assessment will confirm this.

Can I have SMILE if I have dry eyes?

Mild dry eye is not usually a barrier and is often treated for a few weeks before surgery. Severe or untreated dry eye may need to be managed first, and may influence the choice between SMILE and other procedures. The decision is made with your surgeon after tear film testing.

Conclusion

SMILE eye surgery is a well-established, flapless laser procedure for correcting nearsightedness and myopic astigmatism within defined prescription limits. It offers a small incision, generally quick recovery, and a favourable dry eye profile compared with LASIK, while sharing the same overall aim: clear distance vision without glasses or contact lenses.

Whether SMILE is the right procedure in any individual case depends on a careful preoperative assessment, the alternatives available, and a frank conversation with an experienced refractive surgeon. LASIK, PRK, and implantable lenses each have their own strengths and trade-offs, and the goal is to match the procedure to the eye, not the eye to the procedure. With realistic expectations, appropriate candidacy, and good follow-up, SMILE can give long-lasting, stable vision and a meaningful change in daily life.