Laser eye surgery risks

Laser eye surgery is one of the most common and successful elective procedures in the world. Millions of people have had LASIK, SMILE or LASEK, and the vast majority are very happy with their results. However, no surgery is entirely risk-free. Understanding the possible side effects and complications, and how they are minimised, is an important part of making an informed decision.

How safe is laser eye surgery overall?

Modern laser eye surgery is extremely safe when performed by an experienced surgeon on a properly selected patient. The technology has improved dramatically over the past two decades. Treatments are computer-guided, highly precise, and customised to the individual cornea. Serious complications are rare, and the most common issues are temporary and treatable.

The key to safety is patient selection. A thorough pre-operative assessment identifies people who are not ideal candidates, such as those with very thin corneas, unstable prescriptions, severe dry eye, keratoconus, or certain corneal diseases. Excluding high-risk patients is one of the most important ways surgeons keep complication rates low.

Common temporary side effects

Most people experience some mild symptoms in the first days or weeks after laser eye surgery. These are not usually complications, but normal parts of healing. They include:

- Dry eye or gritty sensation, especially in the first month

- Light sensitivity and watering in the first few days

- Mild discomfort or a foreign-body feeling after surface treatments

- Slightly blurred or fluctuating vision during the first week

- Glare or halos around lights at night, which usually improve over time

These symptoms are usually temporary and are managed with lubricating drops, anti-inflammatory drops and time. For most patients, they settle within a few weeks to a few months.

Dry eye after laser eye surgery

Dry eye is the most commonly reported side effect after laser eye surgery. It happens because the laser briefly disrupts the corneal nerves that stimulate tear production. People who already have dry eye, wear contact lenses, or work long hours on screens are more likely to notice it.

Dry eye is usually manageable with artificial tears, omega-3 supplements, warm compresses and lid hygiene. In more persistent cases, punctal plugs or prescription dry eye drops can help. For people with significant pre-existing dry eye, a surface treatment such as LASEK or PRK may be preferred over LASIK because it disturbs fewer corneal nerves.

Night vision symptoms

Glare, halos and starbursts around lights at night are usually caused by the way light interacts with the healing cornea. These symptoms are most common in the first month and tend to improve as the eye settles. They are more likely in people with large pupils, high prescriptions, or higher levels of astigmatism.

Modern laser platforms use larger optical zones and wavefront-guided treatments to reduce night vision symptoms. Choosing the right procedure and treatment profile for the individual eye makes a significant difference.

LASIK flap-related risks

LASIK involves creating a thin corneal flap, which is lifted during the laser treatment and then replaced. The flap is the main feature that distinguishes LASIK from surface treatments. Although it heals quickly, the flap introduces some risks that are not present with SMILE or LASEK.

These include flap displacement in the first day or two if the eye is rubbed or knocked, inflammation under the flap, and small wrinkles or folds. These are uncommon and are usually treatable if caught early. That is why patients are advised to wear a protective shield at night, avoid rubbing the eye, and attend the first post-operative check.

SMILE and LASEK risks

SMILE involves a smaller incision and no flap, so it avoids some LASIK-specific flap risks. The main risks are undercorrection or overcorrection, a small tear in the cap during the procedure, and inflammation. SMILE is newer than LASIK, and the range of treatable prescriptions is narrower, but it is a very safe option for suitable patients.

LASEK and PRK are surface treatments where the outer layer of the cornea is removed before the laser is applied. The risks include more discomfort in the first few days, a slower visual recovery, and a small risk of haze forming in the cornea. Haze is usually mild and can be treated with steroid drops, but it is one reason why surface treatments require careful follow-up.

Rare but serious complications

Serious complications are rare, but they are important to understand. These include infection of the cornea, significant inflammation, scarring, or a weakening of the cornea known as ectasia. Corneal ectasia is the most serious long-term risk because it can progressively distort vision and may require specialist treatment such as cross-linking.

The risk of ectasia is greatly reduced by careful screening. Corneal topography and tomography are used to detect any subtle weakness or irregularity before surgery. People with forme fruste keratoconus or very thin corneas are typically advised not to have laser eye surgery.

Risk factors that increase your chance of problems

Some factors make complications more likely. These include a very high prescription, thin corneas, large pupils, severe dry eye, an unstable prescription, a history of certain eye conditions, autoimmune disease, or unrealistic expectations. Contact lens wear can also increase the risk of dry eye and affect pre-operative measurements, which is why lenses need to be left out before the assessment.

Age matters too. Very young patients may still have a changing prescription, while older patients may be developing cataracts or presbyopia. Laser eye surgery is typically offered to adults between about 21 and 60, depending on the individual situation.

How a good clinic reduces risk

A thorough assessment is the most important safety step. This should include corneal topography, corneal thickness measurement, pupil size measurement, tear film assessment, a dilated retinal examination, and a detailed discussion of your prescription and eye health. The surgeon should explain whether you are a good candidate, which procedure is safest for you, and what alternatives exist.

Experience matters. Surgeons who perform a high volume of laser procedures and who are involved in the full assessment, treatment and aftercare process are better placed to spot problems early and manage them effectively. You should also know what out-of-hours support is available if you have concerns after surgery.

When to seek help after laser eye surgery

Most symptoms after laser eye surgery are mild and settle with time. However, you should contact your clinic urgently if you experience severe pain, a sudden drop in vision, increasing redness, discharge, or any trauma to the eye. These can be signs of infection or another complication that needs prompt treatment.

Next steps

Laser eye surgery is safe for the vast majority of carefully selected patients, but it is not risk-free. The best way to understand your personal risk is to have a detailed, consultant-led assessment. Bring your current glasses and contact lens prescription, be honest about your eye history and lifestyle, and ask about the risks that specifically apply to you. A good surgeon will give you a balanced, honest answer and help you decide whether laser vision correction is the right choice.