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LASIK
Published by Bupa's health information team, July 2006.
This factsheet is for people who are considering LASIK eye surgery or for people who would like information about LASIK.
LASIK stands for laser-assisted in situ keratomileusis. It is a surgical treatment for short-sightedness, some forms of long-sightedness and astigmatism. The procedure uses a computer-controlled laser to correct the shape of the cornea. In many cases, LASIK can reduce the need for glasses or contact lenses.
LASIK surgery animation
How the eye works
The eye bends (refracts) light rays and focuses them to create a clear image on the retina at the back of the eye.
Light enters the eye through a curved clear window called the cornea, which is normally perfectly dome-shaped. When it is out-of-shape, the light bends at the wrong angle, so that the image is not focused properly on the retina. This results in blurry vision.
Glasses and contact lenses refract the light before it enters the eye, helping the eye to focus objects sharply.
 The different parts of the eye
Why have LASIK?
LASIK can help to correct the following eye conditions:
- short-sightedness (myopia)
- long-sightedness (hyperopia)
- astigmatism
LASIK cannot improve presbyopia (age-related long-sightedness) because this is related to the lens of the eye rather than the cornea.
Who can have LASIK?
You have to be aged 21 or over with healthy eyes to be suitable for LASIK. Your vision needs to have been stable (no changes in prescription) for at least a year before the procedure.
LASIK is not a suitable treatment if you have severe short- or long-sightedness or a condition that can make healing difficult (for example, rheumatoid arthritis). You can discuss whether LASIK is a suitable treatment for you at the assessment consultation (see below).
What are the alternatives?
The non-surgical alternative to LASIK for correcting short- or long-sightedness or astigmatism is to continue wearing glasses or contact lenses.
Other types of laser eye surgery include:
- PRK (excimer laser photorefractive keratectomy)
- PARK (excimer laser photo-astigmatic refractive keratectomy)
- LASEK (laser epithelial keratomileusis)
- H-PRK (excimer laser hyperopic photorefractive keratectomy)
Alternatives to laser surgery include:
- phakic lens implants
- lens surgery
What happens before LASIK?
You will be asked to have an assessment consultation with an ophthalmic surgeon (ophthalmologist) to find out if LASIK surgery is suitable for you.
If you wear contact lenses you should remove them around a week before the assessment (depending on the type of contact lenses you wear) as they can affect the test measurements.
The assessment consultation
Your ophthalmologist will talk about the results you can realistically expect during the consultation.
You may have tests including:
- a test that produces a computerised image of the surface of your eye to "map" the cornea
- a full eyesight test
- diagnostic tests, such as measurements of the thickness of your cornea and the size of your pupils in various light conditions
What should I expect in the hospital or clinic?
LASIK is performed as a day case and usually involves a total stay of around an hour.
The procedure
You can have either one eye operated on at a time or both. During the operation, you will lie in a reclined position in a special chair.
LASIK is usually done under a local anaesthetic which numbs the area but you will be awake. Anaesthetic drops will be put into your eye before treatment begins, and a special frame will be used to prevent you blinking during the procedure. It will not be possible to see out of your eye as it is being treated, although you may be able to see a red or green light.
Once the anaesthetic has taken effect, a highly precise instrument called a microkeratome will be used to make an ultra-thin flap (no thicker than a piece of clingfilm) in your cornea. The flap will be "opened" (like the cover of a book) so that the laser can be used to shape the cornea underneath.
The computer-controlled laser, which is known as an excimer laser, will take about 30 seconds to remove precisely the right amount of corneal tissue. The flap will then be repositioned and will bond to the rest of the cornea within minutes. You will not need stitches.
Antibiotic eye drops will be placed in your eye as a precaution against infection.
After the procedure
After the procedure, your eye is likely to be covered with a protective pad. You will need to wear this for around 24 hours.
You shouldn't feel any pain but your eye may be uncomfortable for a few hours. You will be given painkillers if necessary.
Directly afterwards, your vision may be blurred. This should improve gradually over one to two days and your vision will stabilise after about a month.
Before discharge, you will be given a follow-up appointment and eye drops to help prevent infection and promote healing. Your ophthalmologist will give you advice about how to use the eye drops.
It may be helpful to wear sunglasses or a hat when you leave the clinic or hospital as your eyes may be sensitive to the sun. You should not drive yourself home after having LASIK. It is a good idea to have a friend or relative stay with you for the first 24 hours (especially if you have had both eyes treated).
Recovering from LASIK
For the first few days after having LASIK, you should:
- have baths rather than showers
- keep soap and shampoo out of your eyes (it's sensible to not wash your hair for the first few days)
- try not to touch or rub your eyes, or screw your eyes up
- try not to get anything in your eyes - wearing sunglasses may help
- not wear eye make-up
- not play contact sports, swim or play potentially dangerous games, such as squash or tennis, for at least four weeks after the procedure
You should be able to return to work after 2 to 3 days. If you have questions about what you can and can't do, such as when you can drive, ask your ophthalmologist or nurse for guidance.
If you suffer more than mild pain, or you experience loss of vision or increasing redness of your eye, you should contact your clinic or hospital for advice.
Deciding to have LASIK
LASIK is a relatively new procedure and its long-term safety and effectiveness are still being researched. Since its introduction in the UK in 1995, many thousands of people have been successfully treated. However, in order to make a well-informed decision and give your consent, you need to be aware of the possible side-effects and the risk of complications.
Side-effects are the unwanted but mostly temporary effects of a successful procedure. For LASIK, side-effects include:
- dryness of the eye(s) for up to a year after the procedure
- glare around bright lights, causing a "halo" or "starburst" effect that makes night-time driving difficult - this should not last more than six weeks
- a drooping eyelid - but this should stop within a few weeks
Complications are unexpected problems that can occur during or after the procedure. Most people are not affected. The main complications of any operation are bleeding during or soon after the procedure, infection and an abnormal reaction to the anaesthetic. In a small number of cases, complications can lead to reduced vision or blindness.
Specific complications of LASIK are rare but can include:
- mild or moderate haziness or scarring of the cornea
- slight over or under-correction of short-sightedness
- some return of short-sightedness
- accidental damage to the cornea that requires stitches or a graft
- problems with the flap that is made in the cornea
- a deterioration of vision - but this is rare
The amount of improvement in your eyesight depends on how well your eyes heal - it cannot be absolutely guaranteed. If the operation does not achieve the result you hoped you may need further LASIK treatment.
Further information
Sources
- Patient's guide to excimer laser refractive surgery. Royal College of Ophthalmologists. 9 April 2003.
www.rcophth.ac.uk
- LASIK eye surgery. US Food and Drug Administration (FDA).
www.fda.gov
accessed 27 March 2006
- Laser in situ keratomileusis for the treatment of refractive errors. National Institute of Clinical Excellence (NICE). Interventional procedure guidance 102. December 2004.
www.nice.org.uk
- Short sightedness (myopia). UK Department of Health PRODIGY.
www.prodigy.nhs.uk
accessed 31 March 2006
Reviewed by Mr Ahmed Kamal MS, DO, FRCS (Ed), consultant in ophthalmology, BUPA Murrayfield Hospital Wirral.
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