Is laser eye surgery safe? A UK consultant's honest guide to risks, side effects and long-term results

Laser eye surgery is one of the most extensively studied elective procedures in modern medicine, with more than 40 million treatments performed worldwide and over three decades of published outcome data. In the UK, when it is performed on properly screened patients by a GMC-registered consultant using modern platforms, serious sight-threatening complications occur in fewer than 1 in 1,000 eyes and independent audits consistently show patient satisfaction rates above 95%. That said, no surgery is risk-free, and any honest conversation about safety has to cover both the reassuring statistics and the side effects that a minority of patients genuinely do experience.

This guide sets out — in plain English — what modern LASIK, LASEK, SMILE and Presbyond treatments actually involve, what can go wrong, and how careful patient selection dramatically reduces risk. If you would prefer to talk your own case through with a UK consultant, you can book a free 15-minute call or read our full laser eye surgery guide and 2026 UK price guide.

Just how safe is laser eye surgery in 2026?

The UK Royal College of Ophthalmologists, the US FDA and multiple large-scale meta-analyses all report the same headline figures for modern femtosecond LASIK and SMILE: serious, permanent vision-threatening complications in around 0.05–0.1% of eyes (roughly 1 in 1,000 to 1 in 2,000), and patient satisfaction consistently above 95%. In terms of risk-benefit, that puts laser eye surgery in the same safety bracket as contact-lens wear — with the important difference that a contact lens carries an ongoing lifetime risk of microbial keratitis, while laser surgery does not.

The reason those numbers are so good is not luck. It is because unsuitable eyes are turned away. Around 1 in 5 patients who ask about laser eye surgery are told they are not a candidate at their consultation — and that filtering is the single biggest safety intervention in refractive surgery.

The side effects that are common and expected

It is important to separate common, temporary side effects from rare, serious complications. Most patients experience some or all of the following in the first days and weeks:

- Dry eye — the most common side effect. Around 20–40% of patients have noticeable dryness in the first 3 months; fewer than 1% still describe it as troublesome at 12 months. Modern SMILE and surface techniques (LASEK/PRK) produce less dry eye than LASIK. - Glare, halos and starbursts around lights at night — common in the first few weeks, usually settle by 3 months. Persistent troublesome night-vision symptoms occur in around 1–2% of eyes. - Fluctuating vision — normal for the first 4–6 weeks as the cornea heals. - Mild aching or foreign-body sensation for a few hours after surgery, usually well controlled with drops and paracetamol.

The rare complications that matter

These are the outcomes patients actually need to weigh up. On modern equipment, in a properly screened UK patient, they are uncommon — but they are not zero.

- Under- or over-correction requiring an enhancement (retreatment): around 1–3% of eyes. - Flap complications with LASIK (buttonhole, incomplete flap, epithelial ingrowth): under 0.5% with femtosecond flaps, most managed without long-term consequence. - Infection (microbial keratitis): under 1 in 5,000 with modern sterile technique and prophylactic antibiotic drops. - Diffuse lamellar keratitis or inflammation: under 1%, almost always fully treatable with steroid drops. - Corneal ectasia (a rare progressive weakening of the cornea): under 1 in 2,000 with modern screening, essentially eliminated when candidates with hidden keratoconus are excluded by Pentacam corneal tomography. - Permanent loss of two or more lines of best-corrected vision: under 1 in 1,000 in current published series.

How pre-operative screening keeps you safe

A proper UK refractive assessment takes 60–90 minutes and includes at minimum: manifest and cycloplegic refraction, corneal topography and tomography (Pentacam or Scheimpflug imaging), pachymetry (corneal thickness), tear-film assessment, pupil size measurement in dim light, dilated retinal examination and biometry. Patients are turned down for laser if they have thin corneas, forme-fruste keratoconus, significant dry eye, uncontrolled autoimmune disease, unstable prescription, pregnancy or breastfeeding, or very large pupils with a small optical zone. Turning the wrong patients away is what makes the procedure so safe for the rest.

LASIK vs LASEK vs SMILE vs Presbyond — safety differences

All four modern techniques are extremely safe when performed on the right eye. Broadly: LASIK (femtosecond flap + excimer laser) has the fastest visual recovery and lowest post-op discomfort but a slightly higher rate of transient dry eye. SMILE (small-incision lenticule extraction) preserves more corneal nerves and produces less dry eye, and avoids a flap altogether. LASEK/PRK (surface treatment) is preferred for thinner corneas or high-impact sports — no flap to displace — but recovery is slower and more uncomfortable for the first 3–5 days. Presbyond is a LASIK-based blended-vision protocol for patients over 45 who want to reduce reading-glasses dependence and is very well tolerated in the right candidate. Your consultant should recommend the technique based on your corneal thickness, prescription, lifestyle and eye anatomy — not on what the clinic happens to prefer.

Long-term results — does it last?

Published 10- and 20-year follow-up studies of LASIK and PRK show that the refractive result is stable in the great majority of patients. The main long-term change most people notice is presbyopia — the natural age-related loss of reading vision that begins in the mid-40s. Laser surgery does not cause presbyopia and it does not prevent it: everyone eventually needs reading glasses or a solution such as Presbyond blended vision or lens replacement surgery.

Who should NOT have laser eye surgery?

The straight-talking list: patients under 21 (prescription not yet stable), pregnant or breastfeeding women, patients with keratoconus or suspicious topography, patients with corneas thinner than around 480 microns for the treatment planned, patients with uncontrolled autoimmune disease or diabetes, patients with active herpetic eye disease, and patients with unrealistic expectations of perfect vision at every distance forever. In several of these cases lens replacement surgery or a specialist ophthalmology consultation is a safer route to spectacle independence.

Choosing a UK clinic safely

Ask three questions before you commit: Who is my surgeon and how many procedures have they personally performed? (Look for a GMC-registered consultant, not just 'the surgeon on the day'.) What is your rate of enhancements and complications, and can I see it in writing? (Reputable UK clinics audit and publish this.) What is included in the price and what happens if I need retreatment? A transparent aftercare and enhancement policy is one of the strongest markers of a safe clinic.

Related reading: how laser eye surgery works, the Snellen chart and vision correction guide, laser eye surgery, lens replacement surgery, the 2026 UK laser price guide, our full eye service list and consultant ophthalmologist page. Condition guides: keratoconus — the key reason to screen with corneal tomography before laser.

To discuss whether laser eye surgery is safe for your eyes with a UK consultant, book a free 15-minute call or request a full consultation.