Just how safe is laser eye surgery?

Laser eye surgery has been around for many years but is still not without its risks; luckily expert advice is available to help you make the right choices, as Peter Archer reports

Restoring eyesight, without the need for glasses or contact lenses, has long been an everyday reality – no longer far-fetched fantasy. Indeed, life-changing laser eye surgery can now be bought on the high street at an increasing number of clinics.

But the thought of a computer-controlled laser cutting away microscopic amounts of eye tissue remains a chilling prospect.

Laser eye surgery, introduced in its pioneering form in 1989, continues to develop, with increasingly effective techniques, using more accurate lasers and wavefront scanning, for example, becoming widely available.

Safety has improved greatly over the last ten years and treatments can now be accurately targeted. According to the Royal College of Ophthalmologists, the overall risk of something going wrong is less than 5 per cent.

However, even with a fewer than one-in-twenty chance of complications, many people may be nervous about such a delicate procedure. After all, why gamble with your sight? And who do you trust? How do you know which is the best treatment and who is the best surgeon?

Laser Eye Surgery Procedure
Typical laser refractive surgery procedure - The surgeon first makes a corneal flap on the outer layer of the eye and peels it back. An excimer laser is then used to remove tissue from the centre of the cornea to correct any refractive error. The flap is then replaced and the eye is left to heal natural without stitches


It is perhaps shocking – if not completely surprising – that laser eye surgery, like some cosmetic procedures, is not regulated in the same way as most other forms of medical care.

Technically, any surgeon can operate on the eye – there is no law preventing this. “Surgeons may or may not have completed the full UK ophthalmic training to enable them to become an NHS consultant,” warns Professor Sunil Shah of Midland Eye.

“Even if they haven’t completed their training, they can call themselves a ‘consultant’. But they may not be what most people think a consultant in the UK is – someone who has finished their training, is on the Specialist Register for Ophthalmology and working in the NHS.

There are currently some 120,000 laser vision correction procedures carried out in the UK annually

“There is no regulation governing laser surgery and who is able to do it.” Professor Shah advises anyone seeking laser eye surgery to find out what experience their prospective surgeon has.

“Being a consultant doesn’t mean you are an experienced laser surgeon,” he says. “So the number of eyes operated on and number of years performing laser surgery are just as relevant as training.”

Eye surgeons

The Royal College of Ophthalmologists considers that a suitable surgeon is someone who performs at least 500 eye operations a year, ensuring they are experienced and up to date with current developments.

The College awards a certificate of competence after a surgeon has demonstrated competence in assessing patients for treatment, diagnosing eye conditions, carrying out surgery and dealing with complications.

“Patients should be advised to check their surgeon holds this qualification and ask to see it before agreeing to surgery,” the Royal College of Ophthalmologists says. “The College has no direct remit to control professional standards in the laser refractive industry, but has launched an assessment of competence for surgeons in this sector.

“This is the only independent assessment of how competent a laser eye refractive surgeon is.”

Do your research

So, despite the worries, there is a way through the sometimes bewildering maze of e-mails, adverts and other marketing moves urging you to trust in a particular treatment and clinic. But be in no doubt – you have to do your research.

Laser eye surgery
Surgeon performing laser eye surgery

The bad news is that laser eye surgery is generally considered non-essential and is, therefore, usually not available on the NHS. Prices for the various types of treatment range from around £750 to £2,300 per eye.

Procedures are increasing in popularity. Professor Shah estimates there are currently some 120,000 laser vision correction procedures carried out in the UK annually.

“As long as it is performed within certain parameters, which should be well known to the surgeon, then laser eye surgery is very safe from major problems and very effective,” he says.

Laser refractive surgery involves applying anaesthetic drops to the eye and using the energy from a laser to remove microscopic amounts of tissue from the cornea, the clear layer that covers the surface of the eye, to alter its shape. Short sight, when distant objects appear blurred, is treated by flattening the surface of the cornea and long sight, or trouble seeing things at all distances, by making the cornea steeper.

Risks and complications

There are limitations. One in three patients may still need to wear glasses for some purposes, such as night driving, even after treatment. And it is not suitable for everyone.

First, it’s recommended that you should be over 21, in good health and not had your glasses prescription changed within the last one or two years. Your prescription must fall between -1 and -9 if you are short-sighted, and +1 and +4 if you are long-sighted.

Possible complications include dry eyes, when some patients experience dryness for the first couple of months after surgery because the nerves responsible for tear production have to regrow.

There may be problems with night vision, including seeing halos and experiencing difficulty with glare when driving.

The Royal College of Ophthalmologists says around one in five thousand patients develop an infection, but eye drops can help prevent this. Complications with the flap cut in the cornea, during techniques such as LASIK, occur in 0 to 4 per cent of cases, but can normally be corrected with little or no loss of vision.

A serious complication is ectasia, which refers to the thinning of the cornea. This allows the centre to bulge forward, causing poor vision and could lead to sight loss. The National Institute for Health and Care Excellence (NICE) puts the risk of this happening with LASIK at 0.2 per cent.


What’s on offer?


The most common procedure in the UK, LASIK (laser in situ keratomileusis) has been performed since the mid-1990s. Most types of refractive error can be corrected with LASIK. Surgeons cut across the cornea and raise a flap of tissue. The exposed surface is then reshaped using an excimer laser and the flap is replaced.


A form of refractive eye surgery similar to LASIK and also known as Femto-LASIK, this creates a corneal flap with a femtosecond laser microkeratome rather than with a mechanical microkeratome, which uses a steel blade. IntraLASIK can be used to surgically create monovision to enhance the ability to see near and distant objects.


A new treatment in the UK, LASIK Xtra promises to virtually eliminate the risk of serious complications. Eye drops containing a modified version of vitamin B2 are applied after laser treatment and then “activated” by UV light. The treatment has only recently been approved for EU use and could prove to be popular.


This involves chemically removing the top layer of the cornea to create a flap before a laser corrects vision problems. LASEK (laser epithelial keratomileusis) is used when the cornea is too thin for LASIK treatment. A temporary, protective soft contact lens is worn as a “bandage” after treatment to aid healing.


Developed before LASIK and LASEK, PRK (photorefractive keratectomy) involves the cornea being reshaped by an excimer laser without cutting a flap of tissue. The surface layer of the eye grows back during the healing process. Like all laser eye treatments, PRK takes between 15 and 20 minutes, for both eyes, and is performed under local anaesthetic.


This variation of surgery uses sensors to map the contours of the eye. A computer-controlled excimer laser then applies a spatially varying correction. Wavefront is used to treat problems unsuitable for other treatment. It reduces the natural irregularities of the eye, which can cause light rays to focus incorrectly.


1. Your vision may be over- or under-corrected - occurs mostly with PRK and LASEK patients

2. You might end up with visual aberrations - predominant among LASIK patients, although the probability is low

3. You might develop chronic dry, red eyes - occurs among patients of all types of laser eye surgery

4. Your eye may get infected - very rare and can be easily treated with steroid eyedrops or antibiotics

5. You might suffer from corneal estasia - occurs in less than 0.2% of all laser eye surgery patients

Source: Laser Eye Surgery Hub