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- Is Laser Eye Surgery 100% Safe? LASIK Eye Surgery Side Effects, Risks and Success Rates
Is Laser Eye Surgery 100% Safe? LASIK Eye Surgery Side Effects, Risks and Success Rates
No, laser eye surgery is not 100% safe, because no surgery is. LASIK eye surgery side effects such as dry eye, glare and halos are common at first and usually fade within months, while serious complications are rare. A review quoted by the American Academy of Ophthalmology found 99.5% of eyes reached 20/40 vision or better, and about 95% of patients are satisfied. Careful screening by your surgeon lowers the risk most.
Is laser eye surgery 100% safe?
No procedure that changes the shape of the eye can be called 100% safe, and any clinic that promises zero risk is not being straight with you. Laser eye surgery (LASIK, SMILE and PRK) is a well-established operation with a low rate of serious complications, but it is elective surgery on a healthy eye, so it is right to ask what could go wrong before you decide.
Here is how the main medical bodies put it:
- The American Academy of Ophthalmology (AAO) says serious complications are rare, and that side effects are usually temporary but may be permanent in a small number of patients.
- The US Food and Drug Administration (FDA) lists the risks plainly: some patients lose lines of vision that glasses cannot correct, some develop glare, halos or double vision that can seriously affect night vision, some still need glasses or contact lenses, and some develop severe dry eye that may be permanent. The FDA's patient information also states that the long-term safety and effectiveness of LASIK is not known.
- The NHS lists permanent, serious loss of vision, the need for a second operation and under- or over-correction among the risks, and notes that laser eye surgery is not usually offered on the NHS.
"Safe enough" therefore depends on three things you can influence: whether you are a suitable candidate, how well your eyes are tested beforehand, and how experienced your surgeon is. The rest of this guide gives you the numbers.
What are the side effects of LASIK eye surgery?
The most common LASIK eye surgery side effects are dry eye, fluctuating vision, glare, halos around lights and light sensitivity. They come from the cornea healing and its nerves regrowing, and most people notice them in the first days and weeks. The table shows what the research says.
| Side effect | How common | How long it usually lasts |
|---|---|---|
| Dry eye | 60–70% show signs of dry eye in the early weeks after LASIK; a 2024 Community Eye Health review puts some degree of dryness at over 90% after corneal laser surgery | Worst in the first month; improves over 3–12 months |
| New visual symptoms (glare, halos, starbursts, ghost images) | In the two US PROWL studies (534 patients), 43% and 46% reported at least one new symptom at 3 months | Usually settle within a few months (the NHS says several); a minority keep them |
| Changing vision during the day, scratchy eyes | Almost everyone, according to the AAO | Usually fades within a month |
| New dry-eye symptoms in people who had none before | About 28% at 3 months in the PROWL studies | Treated with lubricating and, if needed, prescription drops |
| Needing glasses again (under- or over-correction) | Retreatment (enhancement) rate of about 2.55% in one large analysis | A second laser treatment is possible if the cornea allows it |
Two points keep these numbers in perspective. The PROWL studies counted any new symptom, including mild ones. Dissatisfaction with vision was 1–4%, dissatisfaction with the surgery 1–2%, and fewer than 1% of patients said symptoms made usual activities difficult.
For more on dryness, night-vision problems and what helps, browse our laser eye surgery guides.
What is the success rate of laser eye surgery?
For well-selected patients the success rate is high: the AAO quotes a 2016 review of modern LASIK outcomes in which 99.5% of eyes saw 20/40 or better after surgery. Other studies add detail:
- Visual acuity. In the PROWL studies, 99% and 96% of patients had binocular uncorrected vision of 20/20 or better at 3 months. Across published series for low to moderate short-sightedness, 94–100% reached 20/40 or better; for high short-sightedness the range is lower, 76–97%.
- Satisfaction. About 95% of patients are satisfied with the outcome (EyeWiki, AAO).
- Safety of the sight you already have. In an audit of 53,731 eyes, 0.37% lost two or more lines of best-corrected vision (the vision you reach with glasses). Across 25 studies the median was 0.6%, with a range of 0–3%.
- Predictability. With modern lasers, more than 94% of eyes land within 1.00 dioptre of the intended prescription.
What "success" does not mean. It does not mean a guarantee of 20/20, and it does not mean freedom from reading glasses for ever: LASIK cannot correct presbyopia, the age-related loss of close-up focus. The FDA notes that results are generally not as good for very large prescriptions.
What are the rare but serious risks of laser eye surgery?
Serious complications are uncommon, but they are the reason surgeons screen so carefully. The table lists the ones to know about, with the best published figures.
| Complication | What it is | How common |
|---|---|---|
| Corneal ectasia | The cornea weakens and bulges forward months or years after surgery, causing blurred, distorted vision | About 1 in 5,000 (EyeWiki); 0.04–0.5% in a 2024 review. Most often in young people with high short-sightedness; abnormal corneal shape on scans is the biggest single risk factor |
| Infection (infectious keratitis) | Bacteria or fungi infect the cornea; needs urgent treatment | About 0.02–0.2% |
| Diffuse lamellar keratitis (DLK) | Inflammation under the LASIK flap | 0.4–4.38% in the literature |
| Epithelial ingrowth | Surface cells grow under the flap | Up to 3.9% after a first treatment and 10–20% in re-treated eyes (2024 review); rates after modern femtosecond LASIK are considerably lower |
| Flap problems | Folds, a displaced flap or inflammation around the flap | Reported as possible complications; your surgeon manages them |
| Loss of best-corrected vision | Two or more lines lost on the chart | 0.37% in a very large audit; median 0.6% across 25 studies |
| Severe, lasting dry eye | Dryness that does not settle with treatment | A small minority; the FDA warns it may be permanent |
Most of these can be treated if they are caught early, which is why you should leave with a written drop schedule and a number to call. The AAO also lists, as rare outcomes, infection, vision loss and in the worst cases blindness. These are possible, not typical.
Are SMILE and PRK safer than LASIK?
Not simply "safer": each method trades one set of risks for another, and the best choice depends on your eyes. None is risk-free.
| LASIK / Femto-LASIK | SMILE / SMILE Pro | PRK / surface laser (incl. no-touch) | |
|---|---|---|---|
| How it works | A thin flap is lifted, the tissue underneath is reshaped, the flap is laid back | A small disc of tissue is removed through a 2–4 mm keyhole cut; no flap | The thin surface layer is removed and the cornea reshaped; no flap |
| Flap risks | Yes (folds, ingrowth, DLK) | No flap | No flap |
| Dry eye | Most dry eye of the three | Milder: at 6 months, 80% of SMILE patients had stopped all eye drops versus 57% after LASIK (EyeWiki) | Tends to be milder once the surface has healed |
| Recovery | Symptoms such as dryness and changing vision usually fade within a month (AAO) | Similar to LASIK | More uncomfortable for the first couple of days; surface heals in 4–5 days, vision 20/30–20/50 at first, improving over 4–6 weeks |
| Specific points | Flap-related complications; ectasia risk if screening is missed | Epithelial defects 3.3% versus 4.9% in LASIK; ectasia around 0.15%; 20/20 and line-loss rates comparable with femtosecond LASIK | Mild haze is common and is limited with steroid drops for up to 4 months; less risk of trauma than LASIK because there is no flap |
At Laser Istanbul Clinic, laser surgery is led by Prof. Dr. Ahmet Satıcı and Op. Dr. Aysan Bayram, who offer LASIK, SMILE Pro and PRK, including no-touch surface laser, and choose between them on your scans rather than by habit.
Who should not have laser eye surgery?
Laser eye surgery is not for everyone, and a responsible surgeon will turn you away if your eyes are not suitable. According to the AAO and FDA, laser eye surgery is not recommended, or needs extra caution, if you:
- are under 18 (no laser is approved for LASIK below that age in the US; the AAO says ideally over 21)
- have needed a change in glasses or contact lens prescription in the past year
- have keratoconus or other corneal ectasia, or an abnormal corneal shape on scans
- have corneas that are too thin for the treatment you need
- have severe dry eye, corneal scars or corneal disease
- have advanced glaucoma, a cataract that affects vision, or a history of certain eye infections such as herpes
- have an autoimmune disease, HIV, uncontrolled diabetes or take medicines that affect wound healing
- have a very large prescription
- take part in contact sports such as boxing, wrestling or martial arts (relevant mainly to LASIK flaps)
If laser is not right, other options exist, such as lens-based treatments for very high prescriptions or thin corneas. Your surgeon should tell you this plainly, even if you have already travelled for the examination.
How do you lower your risk of side effects?
Most of the risk is managed before the laser is switched on. A thorough pre-operative examination should include:
Corneal topography or tomography
to map the shape and thickness of the cornea. EyeWiki calls abnormal topography the most significant single risk factor for ectasia, so this scan matters.
Tear-film and dry-eye tests
, so dryness is treated before surgery and the right procedure is chosen.
Pupil size and prescription checks
, because large pupils raise the risk of glare and halos (FDA).
A stable prescription
the AAO advises that your prescription should not have changed much in the last year.
A frank talk about risks
in your own language, with the figures for your type of eye.
After surgery, follow your surgeon's written schedule exactly, use your drops as prescribed and attend every check-up. The NHS adds that you should not drive on the day of surgery or at night until you have recovered.
When you speak to any surgeon, ask:
- Which procedure do you recommend for my eyes, and why?
- What are my own risks, given my scans and prescription?
- Who treats any complication, and where?
- What does the written aftercare plan include?
Is laser eye surgery in Turkey as safe as at home?
The safety of laser eye surgery depends on the surgeon, the screening, the equipment and the aftercare, not on the country. A well-run clinic abroad can be as safe as one at home, and a poorly run clinic at home can be worse. At Laser Istanbul Clinic, surgery takes place in a fully equipped, Ministry of Health–licensed operating theatre in Istanbul, your named surgeon examines you before and after the operation, and checks your eyes again before you fly home. Your coordinator and surgeon then follow your progress remotely.
Our separate guide explains what to check before you book anywhere, from the surgeon's experience to the follow-up you receive.
When should you contact your surgeon?
Contact your surgeon the same day if you notice any of these after laser surgery:
- pain that is getting worse rather than better
- increasing redness, light sensitivity or discharge
- vision that is getting worse, or a sudden drop in vision in one eye
These can be signs of an infection or inflammation, both uncommon but both needing prompt treatment. While you are in Istanbul, call your coordinator; once you are home, contact your surgeon and, if you cannot reach them quickly, go to your nearest eye emergency service.
Book a review if dryness or halos are still affecting you after 3–6 months, or your vision slowly becomes less sharp months or years later, which can be a sign of ectasia.
Frequently asked questions
No. No operation is. Serious complications are rare, but side effects such as dry eye, glare and halos are common at first, and a small number of people have lasting problems. Careful screening before surgery is the best protection.
Dry eye, fluctuating vision, glare, halos and light sensitivity. Signs of dry eye appear in 60–70% of people in the early weeks, and 43–46% of PROWL study participants reported a new visual symptom at 3 months. Most settle within months.
The AAO quotes a 2016 review in which 99.5% of eyes saw 20/40 or better after LASIK, and about 95% of patients are satisfied. In the PROWL studies, 96–99% reached 20/20 or better at 3 months. Results are less predictable for very high prescriptions.
Blindness is listed by the AAO as a possible but rare outcome, and the NHS lists permanent, serious loss of vision among the risks. Typical outcomes are very different: in a very large audit, 0.37% of eyes lost two or more lines of corrected vision.
Most side effects improve over time, but a small number last. The FDA says severe dry eye may be permanent and that glare, halos or double vision can seriously affect night vision in some patients. Ectasia, a rare weakening of the cornea, can appear months to years later.
Both avoid a LASIK flap, and SMILE tends to cause less dry eye (80% off eye drops at 6 months versus 57% after LASIK). PRK is more uncomfortable at first and recovers more slowly. Which is safer for you depends on your corneal thickness, prescription and dryness.
Sometimes: about 2.55% of patients in one large analysis had an enhancement. It depends on corneal thickness and stability. Our sibling guide explains when a second treatment is possible.
People with keratoconus, thin corneas, severe dry eye, an unstable prescription or certain eye and general diseases are generally not suitable. The AAO also advises being at least 18 and ideally over 21.
Want to know whether laser is safe for your eyes?
Send Laser Istanbul Clinic your prescription and scans before you travel. Your surgeon reviews them, tells you honestly whether LASIK, SMILE Pro, PRK or another treatment fits, and explains the risks for your own eyes. Laser surgery is led by Prof. Dr. Ahmet Satıcı and Op. Dr. Aysan Bayram.
Sources for the facts on this page
- US Food and Drug Administration. LASIK: What are the risks and how can I find the right doctor for me? https://www.fda.gov/medical-devices/lasik/what-are-risks-and-how-can-i-find-right-doctor-me
- US Food and Drug Administration. When is LASIK not for me? https://www.fda.gov/medical-devices/lasik/when-lasik-not-me
- American Academy of Ophthalmology. Facts About LASIK Complications. https://www.aao.org/eye-health/treatments/facts-about-lasik-complications
- American Academy of Ophthalmology. LASIK: Laser Eye Surgery. https://www.aao.org/eye-health/treatments/lasik
- EyeWiki (AAO). LASIK for Myopia and Astigmatism: Safety and Efficacy. https://eyewiki.org/LASIK_for_Myopia_and_Astigmatism:_Safety_and_Efficacy
- EyeWiki (AAO). LASIK Complications. https://eyewiki.org/LASIK_Complications
- EyeWiki (AAO). Keratorefractive Lenticule Extraction (KLEx) Surgeries. https://eyewiki.org/Keratorefractive_Lenticule_Extraction_(KLEx)_Surgeries
- EyeWiki (AAO). Photorefractive Keratectomy. https://eyewiki.org/Photorefractive_Keratectomy
- American Academy of Ophthalmology, EyeNet. Postoperative Symptoms and Satisfaction With LASIK Surgery (summary of Eydelman et al., PROWL studies, JAMA Ophthalmology 2017). https://www.aao.org/eyenet/article/postoperative-symptoms-satisfaction-with-lasik-sur
- Ying J, Roy A, Garg P, Chen W. Complications in patients who have undergone laser refractive surgery. Community Eye Health 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11921254/
- NHS. Laser eye surgery and lens surgery. https://www.nhs.uk/tests-and-treatments/laser-eye-surgery-and-lens-surgery/