Laser eye surgery (LASIK)

How LASIK eye surgery is carried out


About LASIK eye surgery

LASIK stands for laser-assisted in situ keratomileusis. It uses a computer-controlled laser to change the shape of your cornea. LASIK can be used to correct or improve:

  • short-sightedness (myopia)
  • long-sightedness (hyperopia)
  • an irregular-shaped cornea (astigmatism) 

To have LASIK you will need to be over the age of 21 and have healthy eyes. You will also need to have stable vision. This means that you have had less than a 0.5 dioptres change in your prescription over the last two to three years. Dioptres (D) is the unit of measurement used for the power of a lens.

LASIK isn't suitable if you:

  • have age-related long-sightedness (presbyopia) – this is related to the weakening of your lens rather than the cornea
  • have a condition that affects how your body heals, such as rheumatoid arthritis
  • are pregnant or breastfeeding

Getting advice about LASIK

You will need to have a consultation with a surgeon to find out whether you’re suitable for LASIK.

Your surgeon will talk to you about the results you can realistically expect from LASIK, as these will vary from person to person.

During your appointment, you may have:

  • a test that 'maps' the cornea to determine if LASIK is suitable for you
  • a full eyesight test
  • diagnostic tests, such as measuring the thickness of your cornea and the size of your pupils in various light conditions

What are the alternatives?

The non-surgical alternative is to continue wearing your glasses or contact lenses. Your surgeon will discuss the range of alternative surgical techniques available with you.

Preparing for your procedure

You will have to remove soft contact lenses at least one day before your appointment and hard/gas-permeable contact lenses at least one week before. This is because your contact lenses can affect the measurements of your eye. Your surgeon will tell you when you should stop wearing contact lenses.

LASIK is usually done as a day-case procedure. This means you have the procedure and go home the same day. LASIK is usually done under local anaesthesia. Anaesthetic drops will block feeling from the surface of your eye and you will stay awake during the operation. The procedure usually involves being at the hospital for around an hour.

Your surgeon will discuss with you what will happen before, during and after your procedure, and any pain you might have. This is your opportunity to understand what will happen, and you can help yourself by preparing questions to ask about the risks, benefits and any alternatives to the procedure. This will help you to be informed, so you can give your consent for the procedure to go ahead, which you may be asked to do by signing a consent form.

Your surgeon will explain how to prepare for your operation. For example, if you smoke you will be asked to stop, as smoking increases your risk of getting a wound infection and slows your recovery.

What happens during LASIK

You may be offered the option of either having each eye operated on separately or both eyes at the same time.

During the operation, you will lie back in a special chair. Your surgeon will place anaesthetic drops into your eye and may use a special eyelid clip to stop you blinking. You won't be able to see out of your eye while it's being treated, although you may see a red or green light.

Your surgeon will use a highly precise instrument with a blade or sometimes, a laser, to cut a very thin flap in your cornea. Your surgeon will open the flap (like the cover of a book) and use the computer-controlled laser to shape the cornea underneath. It will take about 30 seconds to remove the right amount of your cornea.

Your surgeon will then reposition the flap so that it can bond to the rest of your cornea. This takes minutes. You won't need any stitches.

You will have antibiotic eye drops put in your eye to help prevent you getting an infection.

What to expect afterwards

After the procedure, you may have some mild pain and your eye may feel uncomfortable for a few hours. If you need painkillers, take paracetamol or ibuprofen. Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your pharmacist for advice.

You may also find that your vision is blurred which can make you feel disorientated. This should gradually improve within one or two days and your vision will usually stabilise within one to four weeks.

After your procedure you will need to:

  • wear a protective shield over your eye for around 24 hours
  • wear sunglasses or a hat when you leave the hospital or clinic as your eyes will be sensitive to the sun
  • arrange for someone to drive you home
  • have a friend or relative stay with you for the first 24 hours, especially if you have had both eyes treated
  • use eye drops to prevent infection and promote healing – your nurse will give you advice about how to use them before you leave

You will be given a date for a follow-up appointment.

Recovering from LASIK eye surgery

You shouldn't go out into the sunshine without sunglasses after you have had LASIK eye surgery. You will need to wear them for three months. You should also not play contact sports, racket sports or go swimming for at least four weeks, or drive for the first one to two weeks.

For the first few days after having LASIK eye surgery you should not: 

  • have a shower – if you can, have a bath instead
  • wash your hair
  • touch, rub or screw up your eyes or get anything in them – you might find that sunglasses help
  • wear eye make-up

You should be able to return to work after two to three days.

If you experience more than mild pain, or you have any problems with your vision or increasing redness of your eye, contact your clinic or hospital.

What are the risks?

As with every procedure, there are some risks associated with LASIK. We have not included the chance of these happening as they are specific to you and differ for every person. Ask your surgeon to explain how these risks apply to you.

As the treatment is relatively new, there is limited evidence on the long-term effects.


These are the unwanted, but mostly temporary effects you may get after having the procedure.

After LASIK you may have:

  • dry eye(s) for up to a year afterwards
  • a glare around bright lights, causing a ‘halo’ or ‘starburst’ effect, which can make night-time driving difficult but shouldn't last more than six weeks
  • a drooping eyelid, which should get better within a few weeks


This is when problems occur during or after the operation. Most people aren't affected.
Very rarely, complications can lead to reduced vision or blindness.

Specific complications of LASIK are rare but can include:

  • mild or moderate haziness or scarring of your cornea
  • slight over- or under-correction of short-sightedness – you may be offered another operation to improve this
  • some return of short-sightedness
  • accidental damage to your cornea - you may need stitches to keep it in place if it becomes loose
  • problems with the flap that is cut in your cornea
  • your vision getting worse

The amount of improvement that you have in your eyesight depends on how well your eyes heal, but it can't be guaranteed. If the operation doesn't achieve the result you hoped for, you may need further LASIK treatment.

Are ophthalmologists required to have a special qualification to perform LASIK eye surgery?


At the moment, your ophthalmologist (a doctor specialising in eye health, including eye surgery) doesn't need to have any further qualifications to perform laser-assisted in situ keratomileusis (LASIK) eye surgery. However, it's recommended that he or she should undertake additional specialist training in this area.


Although there isn't a legal requirement for ophthalmologists to hold a specific qualification to perform LASIK eye surgery, the Royal College of Ophthalmologists does recommend that surgeons performing LASIK should be fully-trained ophthalmologists and that they should have taken some additional specialist training in LASIK eye surgery. They are also legally required to be registered with the General Medical Council (GMC).

Some surgeons will also be NHS consultants in ophthalmology. This means that they have completed at least eight years of training and have experience of a wide range of eye diseases, as well as experience of eye surgery.

Information on the qualifications and experience that your surgeon has should be on display in his or her office. If it isn't, you can ask to see it.

The Royal College of Ophthalmologists is aiming to introduce a certificate in laser eye surgery which all surgeons performing this type of procedure will need to hold.

After LASIK will my vision be correct for the rest of my life?


The amount of improvement in your eyesight after LASIK depends on how well your eyes heal – it can't be guaranteed. If your operation doesn't achieve the result you hoped for, you may need further LASIK treatment.


The amount your eyesight improves after LASIK will vary and you might get a little over or under the correction you were expecting. You may need to have further LASIK treatment or wear glasses or contact lenses for some tasks, such as reading.

The National Institute for Health and Clinical Excellence (NICE) is an organisation that provides guidance on whether different medical procedures are safe and work well. NICE looked at the results from studies including thousands of people who had LASIK eye surgery.

The evidence showed that, after three to 12 months, 77 out of every 100 people treated for myopia (short-sightedness) or astigmatism (an irregular-shaped cornea) were within 0.5D of the intended correction after treatment, and that 91 out of every 100 people were within 1.0D of the correction they were expecting.

NICE has not reported the results of any studies on people who had LASIK eye surgery to treat long-sightedness.

Presbyopia is when you have difficulty focusing for near work, such as reading, without glasses. It usually occurs when you reach your early-to-mid forties. A younger person with short-sightedness treated with LASIK will effectively become ‘normal sighted’ for reading, but will usually need glasses to read when they reach 40 to 45 years of age. This age-related condition can't be treated with LASIK eye surgery.

If you would like more information on whether LASIK is a suitable treatment for you, or if there are any alternatives, talk to your surgeon.

What's the difference between LASEK, LASIK and epi-LASEK eye surgery?


LASEK (laser subepithelial keratomileusis), LASIK (laser-assisted in situ keratomileusis) and epi-LASIK (epikeratome laser-assisted in-situ keratomileusis) are all techniques that use a special laser called an excimer laser. Your ophthalmologist will advise you on which procedure is most suitable for you.


Laser eye surgery is a technique that changes the shape of your cornea to correct eyesight problems, such as short-sightedness, using a special laser called an excimer laser. The different techniques are explained below.

  • LASEK – your surgeon uses a dilute solution of alcohol to loosen the surface of your cornea, which is then lifted out of the way. He or she is then able to shape your cornea with the laser. A special soft contact lens is kept on your eye for three to four days to allow the surface to heal.
  • LASIK surgery – your surgeon uses a fine surgical instrument or a laser to cut a flap in the surface of your cornea, before using the laser to shape it.
  • Wavefront LASIK – this tailors the laser treatment according to how well your eyes can focus, rather than using measurements based on averages.
  • Epi-LASIK – this is a new procedure where your surgeon lifts the thin, protective outer layer of your cells (epithelium) without the need to apply alcohol and folds it aside using a fine surgical instrument. He or she then applies the laser under the epithelial flap.

The shape of your eye, how short- or long-sighted you are and the thickness of your cornea may affect which type of procedure is recommended for you.

To find out which type of laser eye surgery is most suitable for you, talk to your ophthalmologist.