Is Laser Eye Surgery Safe? What the Risks Really Look Like and What to Expect

Laser eye surgery is considered safe for suitable patients, but it isn’t risk-free. It’s important to understand what those risks actually look like in real terms. Effects such as dry eye, glare or fluctuating vision are commonly reported in the early period after treatment and usually improve as your eye heals. Some people may require further treatment to fine-tune their results. More serious complications can occur, but they are rare.

To give a clearer sense of scale, up to 1 in 10 patients may need an additional procedure to refine their result. This is usually planned in advance and carried out once your vision has settled, rather than something unexpected.

At the other end of the scale, fewer than 1 in 5000 patients require a corneal transplant after laser eye surgery. This would only be considered if the cornea doesn’t heal as expected or becomes unstable in a way that affects how clearly it focuses light.

For many people, their decision also involves comparing surgery with the alternative. Continued contact lens wear carries its own ongoing risk, with around 1 in 3000 wearers each year developing a serious corneal infection. To help you better understand the risks, we’ve put together this guide that looks at possible complications and the elements in place to keep them to a minimum. 

Understanding the risks: what’s normal, uncommon and rare

What’s normal? - Temporary side effects

In the first few days after surgery, it’s normal for your eyes to feel different as they begin to heal and adjust. A light, dry sensation is common and may feel slightly gritty or like your eyes tire more easily than usual. Bright environments can feel harsher, and lights at night may appear with a halo around them. You might also find that your eyes feel more sensitive than usual, or that they water a little more in the early stages.

It’s normal for your vision to feel a little inconsistent at this stage. One day can feel sharper, but then the next could feel like things are slightly less settled. This usually reflects how the surface of your eye is recovering rather than anything going wrong.

These changes tend to ease as healing continues. Your eyes’ surface stabilises, and your vision will become more consistent. These temporary symptoms fade as you continue to use the prescribed eye drops and attend follow-up appointments. 

What’s uncommon? - Treatable complications

In some instances, your vision might not be as sharp as planned after the procedure. Things aren’t quite as clear as you expected, or it could be that one distance feels stronger than another. This usually comes down to how your eyes respond during healing rather than an issue with the treatment itself.

In those cases, it can often be refined with a further procedure once your vision has stabilised. This is sometimes referred to as an enhancement. It involves the same type of laser treatment again to make a small adjustment to the cornea, based on how your eyes have responded to the first procedure.

It’s usually only considered after your eyes have fully healed, so the result can be assessed accurately. The aim is to bring your vision closer to the planned outcome if there’s a noticeable gap after the initial treatment. Not everyone needs one, but the possibility is factored into how results are managed over time.

Recovery can also take a different pace from what you had in mind. The early symptoms may last a little longer, or your vision may take longer to become consistent. That variation is recognised, and your follow-up appointments are there to check how things are progressing and whether any additional support would help.

Up to 1 in 10 patients may need additional surgery to achieve their final result, and this is why this enhancement stage is planned rather than unexpected. Read more about typical laser eye surgery recovery timelines.

What’s rare (serious complications)

Complications that affect the long-term health of the eye are much less common. These types of complications include infection, or more rarely, changes to the cornea shape or a lasting reduction in vision.

Serious complications are much less common and tend to relate to how your eyes respond to treatment. Factors include corneal thickness, how stable your prescription is, and your overall eye health before surgery.

A corneal transplant is only considered in rare situations where the cornea doesn’t heal as expected after treatment or becomes weakened in a way that affects how it focuses light. This is linked to how the cornea responds to surgery rather than the procedure itself. If other treatments aren’t enough to improve vision, a transplant may be needed to restore clarity, although this is very uncommon and affects fewer than 1 in 5000 patients after laser eye surgery.

This kind of outcome is uncommon, and pre-surgery assessment helps lower the chance of it by identifying who is and isn’t suitable for treatment.

If a complication does develop, it’s managed through close follow-up and specialist care. Early review allows treatment to be started at the right stage, helping to preserve vision and support the best possible outcome.

Can laser eye surgery go wrong or cause blindness?

Problems can occur after laser eye surgery, but outcomes that threaten long-term vision are extremely rare. Blindness isn’t something that’s expected in routine laser eye surgery.

It’s understandable that this is a point people focus on when they’re weighing up whether they want to go ahead with surgery or not. The most serious risks tend to stand out when you’re reading about them, even though they’re more at the remote end of what can happen. The problems that develop after surgery are much more likely to be linked to how your eyes heal, how clear your vision feels, or symptoms such as dryness. These are usually picked up early and treated during follow-up, while your vision settles.

When something more serious does develop, it’s rarely without any warning. Changes in your vision, any discomfort that isn’t decreasing, or unusual symptoms are checked during follow-up appointments, and you’ll be advised on what to look out for between visits. This means problems can be assessed and treated before they have a chance to progress.

Suitability checks before your surgery play a large part as well. Detailed measurements of your cornea and a review of your overall eye health are used to decide whether laser treatment is appropriate. If it isn’t, other options are usually recommended instead, which helps reduce the likelihood of more serious complications developing in the first place.

How is safety managed before, during and after surgery?

Laser eye surgery is carefully controlled at each stage, starting with the checks that decide whether it’s suitable for you and continuing through to how your eyes are supported as they recover.

Before surgery 

You’ll have a detailed assessment of your eyes before you begin any sort of treatment. The clinical team will measure the shape and thickness of your cornea, which is the clear front surface that the laser reshapes. The tear film is also checked, as it plays an important role in comfort and healing, and the retina at the back of your eye is examined to rule out any other conditions that would affect suitability. 

These measurements are used to decide whether laser eye surgery is appropriate for you. If the cornea is too thin, the shape isn’t stable, or there are signs of other eye conditions, you may be advised not to go ahead or to consider an alternative treatment instead. The assessment stage is designed to reduce risk before anything else happens.

If you’re feeling anxious about the process, that’s something the clinical team takes into account as well. Numbing eye drops are used during treatment so you don’t feel pain, and in some cases a mild sedative can be offered to help you feel more relaxed. You’ll also be talked through each step so you know what to expect.

During surgery 

If you go ahead with treatment, the procedure is performed using laser systems programmed with the measurements taken during your assessment. The shape of your cornea is adjusted using a plan created specifically for your eye.

During the procedure, the laser is guided using tracking systems that follow small eye movements so the treatment stays aligned. It takes place in a controlled clinical setting, with each step focused on accuracy from start to finish.

After surgery 

You’ll be seen for follow-up appointments after the surgery to check how your eyes are healing and how your vision is settling. These reviews are scheduled at regular intervals over the first weeks and months, which allows your clinical team to closely monitor recovery and spot any complications or issues early. 

You’ll be given eye drops to support healing, reduce inflammation, and limit the risk of an infection. You’ll also be told what symptoms to watch for between visits, so that you can make an appointment for an assessment if you notice anything that doesn’t match the expected patterns. 

How safe is laser eye surgery compared to contact lenses?

Laser eye surgery and contact lenses present different types of risk. Surgery involves a single procedure with a defined recovery period, while contact lens use exposes your eyes to small risks every day. 

Contact lenses sit directly on the surface of your eye. With daily use, this repeated contact can affect the tear film and increase the chances of irritation to your eyes or cause an infection, especially with long wear or inconsistent lens care. Contact lenses are widely used, with most people able to do this daily without any issues - but they do carry a small ongoing risk. A large review of contact lens–related infections found that each year, between around 1 in 5000 and 1 in 500 wearers develop a serious corneal infection.

Whilst this means the overall risk is low, it is still present and continues for as long as you wear contact lenses. 

The possible risks of laser eye surgery are essentially limited to the procedure, followed by a period of healing and monitoring. Beyond this, there isn’t the same ongoing interaction with the surface of the eye that comes with daily lens wear.

How side effects change over time

Post-laser eye surgery side effect symptoms change as you recover, and your eyes won’t feel the same way long-term as they do in the days after your procedure. 

Your eyes are usually at their most unsettled in the first 24-48 hours. They can feel dry or slightly scratchy, and your vision may seem hazy or uneven. This has been compared to looking through a lightly fogged surface. In the short term, bright lights can feel stronger than usual, and it’s common for things to look less consistent than the expected final result. 

As you continue to heal, your vision becomes more stable, and those early symptoms start to ease. Your eyes might still feel dry by the end of the day, and lights might still feel like they have a flow around them, but both should be decreasing.

By around 3 months after treatment, things usually feel much more settled. Your vision tends to feel clearer and more consistent, although there can still be slight day-to-day differences.

After surgery, your symptoms should gradually settle rather than move in the wrong direction. If your vision worsens after starting to improve, discomfort becomes stronger instead of easing, or something simply doesn’t feel right, contact your clinic so your eyes can be checked."

Why are laser eye surgery outcomes more predictable today?

Laser eye surgery is now planned and performed with a much higher level of precision than in the past. The main difference is the level of detail your surgeon has about your eyes before treatment, and how accurately the procedure can follow that plan.

Before laser-based methods became standard in the 1990s, a mechanical blade was used to create the corneal flap, and the result could vary slightly from one treatment to the next. Modern procedures use a computer-guided laser for this stage, allowing the flap to be created with a more consistent shape and depth.

The way treatment is planned has also changed substantially. Earlier procedures relied mainly on a glasses prescription, but detailed scans now measure how light travels through your eye and map the shape of the cornea. This means treatment can be based on how your eye actually focuses rather than a single measurement.

Modern imaging can detect subtle changes in the cornea, such as early keratoconus or areas where the tissue is thinner than expected. People at higher risk of complications are usually identified before treatment and advised not to go ahead.

Earlier procedures treated a smaller central area of the cornea, which made visual effects such as glare or halos more noticeable, particularly in low light. Treatment zones are now wider, covering more of the cornea, and blend more gradually at the edges, which has made glare and halos far less common. Tracking systems follow small eye movements during the procedure so the laser remains aligned throughout.

Wavefront-guided and ray-tracing approaches can now build a detailed digital model of your eye using tens of thousands of data points, allowing treatment to be matched more closely to how your eye focuses light. In a recent study presented at the American Academy of Ophthalmology, 98% of eyes treated with the latest ray-tracing guided LASIK reached within a quarter-dioptre of the intended prescription. A quarter-dioptre is the smallest step used in most glasses prescriptions, so this means the final result was extremely close to the planned level of correction.

No two eyes are identical, but the consistency of results today reflects how much has changed: every stage, from screening through to the procedure itself, is shaped by measurements specific to your eye.