LASIK (laser in-situ keratomileusis) is the most common form of refractive surgery – that is surgery performed to correct refractive errors to reduce the dependence on glasses and contact lenses.
Modern laser refractive surgery is very safe and effective, with most people being extremely happy with the results. We commonly hear that it is the best thing people have ever done and that they wished they had done it years ago. It usually makes a huge difference to people’s quality of life.
You do need to be aware, however, that it is not perfect, despite what you may have seen or heard. Even though we use the most up-to-date technology and lasers there is some variability in the results and not everybody’s vision is perfect afterward. This is mostly because the procedure is performed on living tissue. Corneas are different in ways we cannot measure and react to the laser variably. Also, the healing responses afterward can alter results slightly.
What this means is that your unaided vision after LASIK may not be quite as good as it is now with your glasses or contact lenses and it may not be possible for us to make it that good. Almost always the vision in one eye will turn out to be slightly better than the other when tested individually but most people are not aware of this with both eyes open.
We do expect to be able to make you able to function very well in most situations without glasses. People with high prescriptions may need to wear glasses in some situations, such as for driving at night. Those older than 45 years or so will need glasses for near vision at some stage unless they have a monovision correction.
Not everybody can have, or should have, laser refractive surgery.
You may not be suitable if your spectacle prescription measurements are out of the range that can be corrected, or if your corneas are too thin, or have abnormal topography. There may be other issues with your eyes that may mean that it is not a good idea to have the surgery, for instance: severe dry eye, glaucoma, or retinal problems. We will usually not perform refractive surgery if one eye is significantly amblyopic (lazy). If there is any sign of cataract (opacity in the lens inside the eye) then it is not sensible to have LASIK. It does not work as well for long-sightedness (hyperopia) as it does for short-sightedness (myopia).
If you are very young or have a high correction we may advise waiting to be sure your refraction is stable. We will generally not treat those younger than 20 years and may advise waiting for those older than that depending on individual circumstances.
The surgery may not be able to achieve what you want it to do – most commonly this relates to being unable to improve near (e.g. reading) vision for people older than 45 years.
If you cannot accept that your vision may not be perfect afterwards then you should probably not do it. It is important that you have a reasonable expectation of what can be achieved so that you are happy with the result.
The laser procedure is performed as an outpatient procedure at Lions Eye Institute. You will be here for 1-2 hours. You will have some oral sedation and analgesia and will need someone to drive you home and to bring you back again the next morning as your vision will still be a little hazy.
The LASIK procedure itself takes about 25 minutes for both eyes and is performed with local anaesthetic eyedrops (the same as we use in the clinic). You will be lying comfortably on a bed during the procedure and the surgeon will talk you through each step. The anaesthetic drops stop you feeling the need to blink and your eyes will be held open so that you cannot blink. Flaps are prepared in both corneas using the Intralase iFS laser, then the refractive change to correct your vision is made with the Schwind Amaris 1050RS excimer laser as a sterile procedure. The laser part itself will take 5-20 seconds. You will need to be able to lie quite still and keep your eye steady while looking at a target light for this part of the procedure. The laser tracks your eye movements during the treatment but it is important to keep as still as possible. The procedure is usually not painful but there are some unpleasant sensations, including some pulling and stretching of the eyelids, pressure, and very bright lights. Most people say it is not as bad as they expected.
At the end of the LASIK procedure you will have transparent plastic shields placed over your eyes to protect them. You will be able to see but not very well. Your vision will not be good until you have had a sleep and usually that will mean until the next day and even then your vision will not be quite as good as it is going to be. The local anaesthetic we use wears off within an hour after the procedure and then your eyes will start to feel irritable and very light sensitive. You will find it very difficult to keep them open and they will water for several hours afterwards. It is best to go home and rest with them closed for a few hours. You will be given some analgesic tablets (we use Panadeine, so tell us if you cannot take codeine) and can take more of these, or any analgesic you are comfortable with, such as Panadol or Nurofen, later.
It takes some days for the flaps to settle and smooth out. Your vision will continue to improve day by day for a week or so after the procedure. You will be aware of further subtle improvement for up to 3 months. Vision in bright light will be good very quickly but night-time vision takes longer to improve and it is often a few months until that is as good as it is going to be. Distance vision takes longer to improve for hyperopic (long-sighted) treatments than for myopic treatments and may take months to be as good as it is going to be.
Expect some variability in your vision in the first few days afterward. It will initially be a little hazy and will seem to fluctuate even as you blink. You may find it more difficult than usual with prolonged computer work or reading to start with and may notice that your eyes get tired easily. It is best to take more than one day off work if you have to do a lot of computer work, especially if you are working in an air-conditioned environment. This will all possibly be worse for people who are older than 40 years.
The corneal flap can be shifted or dislocated with a firm rub on the eye in the first few days after the procedure so you need to be very careful with it during this time. We will ask you to wear the shields at night for at least 2 more nights. There is not a great deal of restriction on your activity, though. It is fine to exercise but be careful about rubbing your eyes if you are sweating. Do not swim or use a spa for 2 weeks as this could introduce infection. After a month or so you would have to injure your eye with something hard or sharp to cause trouble with the flap and the trauma would have to be severe enough that it would damage your eye anyway. We advise no surfing for 2 weeks and no diving or contact sport for at least 1 month after the surgery.
It takes 3 months or more for your vision to completely stabilise after the procedure but most of the change happens in the first month. After this you should not be aware of any change in distance vision for a long time. The effect of the LASIK surgery does not wear off but your eyes can continue to change with age. This is more likely the younger you are when you have it done, or for those who are very short-sighted to begin with, or for hyperopic (long-sighted) corrections. If your eyes do change then it may mean that glasses, or another laser treatment, may be necessary years down the track. This is less likely for those with lower levels of short-sightedness. In the very long run there will be changes in the lens inside your eye that may alter the focus when cataracts start to develop. That may then require cataract surgery.
Near vision usually starts to deteriorate in mid-to-late 40’s. When that starts it will be necessary to use glasses for near vision in some circumstances and the need for these will gradually increase as you get older. At present, we have no way of fixing this (presbyopia) completely.
LASIK is a very safe procedure but there is a small risk of having problems either during the procedure or afterwards. These problems may just be a nuisance but some could permanently affect your vision and/or comfort:
It is possible that you might end up being over or under-corrected as far as the focus of one or both eyes is concerned. If you are aware of this and are uncomfortable with it then this can be retreated with more laser if everything else is satisfactory and there is enough thickness in the cornea. We generally wait for at least 3 months for the focus to be stable. Overall, about one in forty will need a retreatment but this is more likely for higher level corrections. There is no charge for this in the first year after the procedure. Depending on the thickness of the cornea this may be done by lifting the flap or doing a surface ablation (PRK) procedure.
With the laser method of corneal flap creation problems are rare. If there is a break in suction during the procedure it may need to be repeated. It is possible that a problem with the laser itself could mean that a flap is not created properly and it may not be possible to complete the procedure on that day and it would need to be done a few weeks later. Rarely, it would mean that a LASIK procedure is not advisable but that a surface laser procedure (PRK) would need to be used to complete the treatment.
Everybody’s eyes are drier after the laser procedure. This is because the reflex production of tears is reduced by cutting through the nerves in the cornea. These nerves take 1-2 years to regenerate. Most people will not be aware of any problem with this but those who have dry eyes to start with and those who are older than 40 years are more likely to have some symptoms of dryness. It is more bothersome for people who use computers a lot and who work in air-conditioned offices. It may be necessary to use lubricating drops for some time after the procedure. It may help to take omega-3 fatty acid supplements (fish oil or flaxseed oil, 3,000mg daily, krill oil 1,000mg daily, or Lacritec 3 capsules daily). If you have had any dry eye issues before then it helps to start using lubricating drops and omega-3 supplements before the laser treatment.
Infection could occur but is very rare and is treatable with the appropriate antibiotics. It could lead to scarring that may require corneal transplantation.
The epithelium is the surface covering of the cornea. This should be firmly stuck down but in some people is relatively loose. This can mean that the epithelium can shift or be dislodged during the procedure. This makes the eye more uncomfortable than usual and slows down recovery. A bandage contact lens may be used to protect the loose surface and other treatment may be required later to stabilise it. This issue can lead to a delay in improvement and stabilisation of vision after the laser procedure and may require further treatment.
The edge of a corneal flap may be wrinkled up with minor trauma in the first few days. If this happens it will need to be lifted and smoothed out. This is done in the laser suite. It will mean a delay in recovery but generally does not cause long term problems.
Inflammation in the flap interface is called diffuse lamellar keratitis (DLK). We occasionally see mild cases of this that are easy to treat with more of the drops that we usually use postoperatively. There have been some severe cases of this reported and those have required more extensive treatment, including lifting of the flap to clean out the interface. In severe cases there may be hazy scarring of the interface that could interfere with vision permanently.
This refers to the cornea warping out of shape if it is made too thin by the laser procedure. If that happens then hard contact lenses are required to obtain good vision as glasses or soft contact lenses do not work well. There are some newer treatments for this problem but in severe cases corneal transplantation may be required. Subtle changes in the shape of corneas may suggest that this is more likely to happen and we look very carefully for any sign of this in your initial assessment. A family history of keratoconus is also a risk factor for this. We advise people in that situation not to have LASIK. Similarly, if corneas are too thin for the refractive correction required we advise against having LASIK. In that case it may be possible to perform surface laser (PRK) instead.
Loss of best corrected vision
A few people will have poorer best-corrected vision after LASIK. This means that the quality of vision at best afterwards is not as good as it was before. Most people are not aware of this as the unaided vision is still so much better than before but occasionally someone will be aware that the quality of their vision is not as good as it was. The important thing about this is that it is not correctable with glasses or contact lenses and may not be fixable with laser retreatment. This is more likely to happen with very high level corrections.
Night vision problems
This was a significant issue in the early days of laser refractive surgery and with the old radial keratotomy (RK) procedure but it is rarely a problem now. Night vision does take longer to improve than daytime vision after the treatment but usually is as good as it was with glasses or contact lenses before.
There may be other problems that could affect your vision or ocular comfort after LASIK.
Once every year or two we will have a technical problem with one of the lasers on the day of surgery. That may mean that a treatment list, or part of a list, has to be postponed. That is a major nuisance for those affected but is unfortunately unavoidable even with the best regular maintenance.