Yes. The loss of reading vision occurs due to ageing, as the eye begins to lose its ability to ‘zoom’ from distance to near. This means that the close vision deteriorates. Some clinics choose to treat presbyopia by removing the natural lens inside the eye and replacing it with an artificial one.

However, there is also a laser eye surgery procedure called PRESBYOND® Laser Blended Vision, which is highly effective and much less invasive than lens replacement. With this technique, one eye is treated to view objects mainly at distance and a little up close, while the other is treated to view objects mainly up close and a little at distance. The brain learns to combine the two images, enabling the individual to see far and intermediate distances and up close, without effort. Studies have shown that 97% of people are suitable for PRESBYOND® Laser Blended Vision, and almost all are able to read normal newsprint without glasses after surgery.

The vast majority of patients undergoing laser eye surgery worldwide are suitable for LASIK, and most short-sighted patients are also candidates for SMILE. In the past, patients with thin corneas tended to be recommended for surface procedures (PRK, LASIK and Epi-LASIK) as these do not require the creation of a corneal flap.

Many of these patients can now be treated with SMILE – a totally ‘flap-less’, keyhole procedure, which was first introduced in the UK at London Vision Clinic in 2011. However, a small minority remain candidates for surface treatments only, and some patients may only be suitable for an intraocular lens procedure, either an ICL or CLE.

Yes. Large scale studies conducted over a decade ago demonstrated that there was no difference in safety between singleeye surgery and bilateral surgery. In fact, some evidence suggests that it is actually safer to treat the second eye immediately following the first eye. There are, of course, certain situations where your surgeon may suggest treating one eye at a time, but this would generally be due to specific medical issues.

There is no pain involved during laser eye surgery. You will be given a topical anaesthetic to numb your eyes – most patients report feeling some pressure on the eye (which can be a strange sensation) but not pain. Many LASIK and SMILE patients do not experience any discomfort after surgery – although it is normal to experience some grittiness, light sensitivity and eye watering for the first 24 hours. After surface procedures (PRK, LASEK and Epi-LASIK), the eyes take a few days to heal. However, patients should not find the healing process painful, as they are given pain-relief medication and fitted with bandage contact lenses.

The treatment takes only minutes and the laser itself is only active for seconds

Nothing. Although your eye will move during surgery, eye tracking technology ensures your safety when this happens – the laser tracks your eye hundreds of times every second, and compensates for any movements. In the SMILE procedure, the eye is immobilised by the vacuum connection to the laser.

Laser eye surgery is safe, but no surgery is entirely without some level of risk. Thankfully, an expert surgeon will have the knowledge to manage complications properly, and will usually be able to correct any complications that do occur. In the hands of an expert surgeon, the chance of something going noticeably wrong is around one in 1,000 procedures. The chance that such a surgeon would be faced with a situation he or she would not be able to correct satisfactorily is about one in 30,000.

Rules about this will vary between clinics. Generally it is better to not use sedatives, as these can alter patient cooperation during the procedure. However, patients who suffer from anxiety disorders such as panic attacks, claustrophobia etc. may benefit from judicial use of sedatives. If this applies to you, your surgeon should discuss the risks and benefits of sedatives thoroughly with you, before surgery. Never self-medicate. Your medical team should provide the necessary required medical dose

Yes. In general, results decrease as prescriptions increase. Results also differ between short-sightedness and longsightedness. Therefore, when reviewing a clinic’s results, it is important to look at results for prescriptions that are similar to yours as these will provide you with a more accurate picture of your chosen clinic’s success rates.

Wavefront treatment has received a lot of publicity. However, it is important to remember that not all wavefront systems are as good as each other (see Technology section earlier). Wavefront sensors measure the unique optical imperfections of your eye, called ‘higher order aberrations’. These irregularities of your optical system affect the finer quality of your vision, beyond what glasses are able to correct. The most advanced wavefront technology can be used to customise your treatment to account for these higher order aberrations, meaning a safer and more accurate treatment

Yes. Laser eye surgery can treat astigmatism at the same time as it corrects short or long-sightedness. No extra procedure is needed.

In most cases, having a very high prescription will not stop you having laser eye surgery. The range that any surgeon can treat depends on their technology and experience, but technology and expertise in the field is now so advanced that the vast majority of patients with very high prescriptions are now suitable for a ‘full correction’ and, for those patients with extremely high prescriptions, laser eye surgery can still be used to achieve a significant improvement in the vision, or an intraocular lens procedure could achieve a full correction, either an ICL or CLE. If you are turned away by a clinic, it is important to remember that this often does not mean that you are not suitable – it may simply mean that your chosen clinic does not have the technology or experience necessary to treat you safely

The majority of laser eye surgery is performed on patients with:

• Myopia up to -8.00 D
• Hyperopia up to +3.00 D
• Astigmatism up to -4.00 D.

However, some surgeons have the expertise and technology that allows them to safely treat much higher prescriptions – a full correction is sometimes possible on prescriptions of:

• Myopia up to -14.00 D
• Hyperopia up to +6.50 D
• Astigmatism up to -6.00 D.

If your prescription is higher than this, you should not be disheartened as it may be possible to significantly improve your vision with a partial correction. Alternatively, you can consider intraocular procedures such as an ICL or CLE, which can be used to correct almost any prescription.

Laser eye surgery patients must be at least 18 years old; there is no upper age limit

Yes. Presbyopia typically develops during the 40s (although some patients do not begin to lose their reading vision until their mid-50s). When presbyopia develops, people begin to need glasses for reading even if they have never worn glasses before. People who previously wore glasses will need a different prescription for reading than for distance (e.g. bifocals).

Laser eye surgery is, by any medical standard, a safe procedure. However, as with all surgical procedures, there are some risks to consider. Fewer than 3% of LASIK procedures result in any complications. The chance of having a serious complication is much less than 1% generally and probably less than 0.3% with an expert surgeon. The most common complications and sideeffects of laser eye surgery are as follows:

• In about 1 in 1,000 LASIK cases, the flap is too short, thin or uneven. If this occurs, the flap is put back in place to heal. The surgeon will not use a laser on your eye and your vision will likely be unaffected, but you can try surgery again in a few months.
• Wrinkles in the flap (striations) occur in about 1 in every 1,000 LASIK procedures. Striations can cause astigmatism. The most likely causes are either rubbing your eyes before they are fully healed, or the surgeon not lining up the flap properly when it is replaced. If the wrinkles are causing astigmatism, a second procedure can be done to lift and smooth out the flap. If they are not causing any problems they can be left untreated.
• In about 1 in every 5,000 cases, patients develop irregular astigmatism after surgery. Contact lenses can usually correct this form of astigmatism (glasses will not). People who have very high prescriptions have a higher risk of this complication. Irregular astigmatism can happen even if the surgery is perfect, but your risk is increased if you have an inexperienced surgeon or one who does not use the best equipment.
• Epithelial ingrowth is a potential complication of LASIK that occurs in less than 1% of cases, in which epithelial cells begin to grow and multiply under the corneal flap. The most common treatment is lifting the corneal flap, removing the cells, irrigating the interface and repositioning the flap. Most cases, if managed appropriately, have a good outcome.
• Ectasia, which occurs in about 4 in 10,000 cases, is a progressive deformity that makes the cornea thinner and steeper. It can be treated with corneal crosslinking (CXL), by suturing (stitching) the flap to the underlying cornea, or in rare circumstances with a corneal transplant. When identified early, it is very unlikely to lead to further visual degradation with appropriate treatment. Ectasia is more likely to occur in eyes with a condition known as keratoconus. Therefore, it is important to undergo intensive and detailed screening for keratoconus before surgery. Currently, the most sensitive method for detecting keratoconus is to use thickness maps of the epithelium in combination with topography and tomography (see the sections on technology). This method was pioneered by Professor Reinstein and has become accepted by ectasia experts around the world as an important component to keratoconus screening. As with any surgical procedure, there is a risk of infection after laser eye surgery. The risk of a corneal infection is approximately the same as one year of soft contact lens wear (about 5 in 10,000 patients). As with any ophthalmic procedure there is a very remote risk, estimated as less than 1 in 4,000,000, of the loss of an eye, with partial or total blindness.
• Most laser eye surgery patients experience some temporary dryness after treatment. In certain people, the condition is long-lasting. Eye drops can provide relief, but up to 5% of patients have persistent dry eye symptoms up to 1 year, and 1% longer than 1 year.
• Glare and halos are probably the most common side-effect of laser eye surgery. Most patients indeed experience some level of glare and halos at first, but this generally goes away over a period of a few weeks to a few months. Those who do have lasting effects usually only experience symptoms at night, and most do not find them troublesome. Symptoms can usually be improved by further surgery. The causes are below.

There are several reasons why a patient might develop glare and / or halos after laser eye surgery:

If you have been ‘under-corrected’ (i.e. if the shape of your cornea has not been changed enough during your procedure), you may still be slightly short or long-sighted and/or still have a minor astigmatism.

A minor enhancement procedure can usually address this. For the small minority of patients who are not candidates for an enhancement, wearing glasses can generally get rid of any troublesome symptoms.

The size of your pupils can be another cause of glare and halos. If a patient’s pupils dilate (open) beyond the area of the cornea that has been treated during laser eye surgery, this can cause glare and halos in low light conditions. The risk of this can be mitigated by accurately measuring your dilated pupil size before surgery. The surgeon can determine whether or not they can effectively treat a large enough area of your cornea with the laser, and if this is not possible then the surgeon should decide not to treat you. Frequently Asked Questions

If you do have glare and halos at night because of your pupil size, there are a few techniques that can help. Some patients find that keeping the overhead light on inside their car when driving stops their pupils dilating so much that it affects their vision. There are also medicated eye drops that stop the pupil from dilating fully, and some patients find that these fully alleviate the problem. Alternatively, clinics with access to an excimer laser that includes a topography-guided treatment option can perform a second treatment that can reduce these symptoms.

Finally, glare and halos can be caused if the area of your cornea treated by the laser is off to one side (known as ‘off-centred ablation’ or ‘decentration’). Choosing a properly qualified and experienced surgeon can help to minimise the risk of this serious complication. Specialist clinics will be able to perform a topography-guided treatment to re-center the treated zone and improve the quality of vision.

In general, using advanced wavefront technology can significantly reduce the risk of glare, halos and night vision difficulties resulting from surgery (see Technology section for further detail).

Initially, the flap is kept in position by a vacuum effect. The cells lining the inner surface of your cornea – known as endothelial cells – pump water out to the inner part of the eye. This creates suction, which holds the flap in place. During the first few hours after surgery, the outer surface of the cornea – known as the epithelium – seals the edges of the flap. Over the ensuing weeks, natural substances inside your cornea bond the flap to the underlying tissue

The following list includes conditions or circumstances that prospective patients commonly ask about when discussing suitability for laser eye surgery