Refractive Laser Surgery

Laser refractive surgery can permanently correct short sight (myopia), long sight (hypermetropia or hyperopia) and astigmatism (uneven focusing power). That means that after a quick outpatient procedure which lasts around 20 minutes you’ll be able to see clearly in the distance without glasses or contact lenses.

Moorfields Private's refractive laser service now offers LASIK, Wavefront LASIK and intra-LASIK, and surface wavefront laser treatments (PRK, LASEK). We also offer intraocular refractive surgery such as ICL and TICL implantation in the young patients and RLE (Refractive Lens Exchange – procedure identical to cataract surgery but for the purpose of improving spectacles independence for either patients with abnormal corneas or for high refractive errors that are beyond the range of the laser. These procedures are always carried out by experienced Consultants that hold NHS Consultants appointments at Moorfields Eye Hospital and who are experts in the field of refractive surgery and corneal surgery.

Our long history of being at the forefront of eye care and ophthalmic surgery, and the fact that our surgeons are amongst the most experienced in the world in these techniques, means that for peace of mind  there is simply nowhere better to visit for laser vision correction than Moorfields Eye Hospital.

We see when the eye’s optical system forms an image on the retina, which is a carpet of light sensitive cells lining the inside of the back of the eye. Images are focused on the retina by the cornea – the clear part at the front of the eye – and the natural lens suspended in the eye just behind the pupil.

It is the shape of the cornea that determines its focusing power. Together with the power of the natural lens and the overall size of the eye, this determines whether we have normal or impaired sight. A number of laser surgery techniques have been developed to correct short sight, long sight, and astigmatism by altering the shape of the cornea.

At the moment laser vision correction cannot reverse the visual changes caused by the normal aging process. We all experience an increasing reliance on reading glasses, usually from our mid forties. While people who have laser treatment to correct their reliance on contact lenses or glasses will retain good distance sight, they too will also need glasses for reading in later life. (Some patients choose to be corrected for near vision rather than distance vision).

Your consultation at Moorfields will examine your lifestyle needs in detail – for example, your reading and distance vision requirements – and help you to arrive at the best choice for your laser correction.

There are several different types of refractive surgery. Your Moorfields Private consultant will advise you on which is most suitable for you.

LASIK or intra-LASIK or BLADELESS LASIK (Laser Assisted In Situ Keratomileusis) can correct short sight, long sight and astigmatism, accounting for around 95 per cent of refractive error. This technique is the most modern and involves the use of the latest femtolaser technology to create a thin flap in the cornea , the flap (hinged on top) is the lifted and the wavefront excimer laser s used to reshape the corneal bed under the flap and ensure correction of the optics of the eye.

Wavefront LASIK improves on conventional LASIK by tailoring the treatment to correct some elements of focusing that are averaged, rather than corrected individually, in your spectacle prescription.

Surface laser treatments such as LASEK are further alternatives – the recovery period is longer than for LASIK, but surface laser treatments may be safer if your cornea is relatively thin, or if other medical conditions predispose you against LASIK. Surface treatments are also recommended for people who lead active lifestyles where there is potential risk of eye injury – for example, professional sports people, police, armed forces, etc.

For the correction of higher refractive errors and for patients who are not suitable for LASIK the options is intraocular refractive surgery such as ICL and TICL implantation in the young patients without removing the natural crystalline lens and RLE (Refractive Lens Exchange – procedure identical to cataract surgery) when a lens not cloudy is removed and an artificial lens in implanted in the eye.

For laser refractive surgery, you will normally be in hospital for around 1 hour. Implant based procedures, which may be under general anesthetic, usually require a longer stay of typically 4-6 hours.

LASIK/Intra-LASIK (Laser Assisted In Situ Keratomileusis) is the most advanced refractive surgery procedure currently available.

It is also a very successful technique: quick, painless, and most patients are completely delighted with the results. The treatment is carried out as an out patient procedure and both eyes are usually treated at the same time. You will be able to play sport and socialise without glasses a short time after the treatment – full visual recovery is usually just 2 – 7 days.

Originally a precision surgical device was used to create a small 'flap' in the surface of the cornea, and excimer laser treatment was then applied underneath. Now however the routine method used at Moorfields to create the corneal flap involves another laser – the femtosecond laser – which is more accurate and therefore safer. The technique is termed intra-LASIK. Moorfields has recently installed the latest version of this laser – the Abbott AMO iFS femtosecond laser (at present the only example in the UK). The computer-guided excimer laser beam is then focused on the corneal surface and permanently reshapes the cornea by precise selective tissue removal. When the laser treatment is finished, the flap is repositioned, where it settles back into place, and the procedure is complete. LASIK takes around ten minutes for each eye.

While LASIK is very safe, careful patient selection and an intimate knowledge of strategies for avoiding complications are essential. This is why Moorfields Private believes you should have the treatment performed in a hospital setting, by an experienced consultant ophthalmic surgeon who is supported by a fully trained ophthalmic nurse at all times.

Wavefront scanning is a new technology which reveals how your entire optical system processes light.

A Wavefront scan produces a map of the actual focusing requirement at each point on your eye, which is different for every individual. It can be compared to having a fingerprint taken for each eye.

Wavefront LASIK and surface treatments build information from a Wavefront scan into the pre-programmed pattern of laser treatment used to correct your sight. The procedure is otherwise identical to conventional excimer laser treatment, and is used to correct the same range of refractive errors.

The advantages of Wavefront over conventional laser treatments are thought to include greater accuracy and improvements in visual quality. Wavefront treatments also include additional elements such as iris registration, or even iris recognition, and pupil size measurement in order to be more precise. The latest excimer lasers in use at Moorfields for example can offer ‘dynamic rotational tracking’ of eye movements in order to achieve greater accuracy. It should be emphasised, however, that conventional laser refractive surgery already produces very good results and that Wavefront treatments do not routinely produce supervision, or vision that is better than the normal level for a non-spectacle wearer.

LASEK and PRK are similar procedures to LASIK, but the laser treatment is carried out on the surface of the eye after removing a thin layer of epithelium (a protective layer of skin at the front of the eye) from the cornea. These options are generally used for patients who have normal but relatively thin corneas or who lead an active lifestyle which includes contact sports, and therefore might be unsuitable for LASIK.

These treatments are just as simple to perform. The recovery period is longer than that of LASIK, because the surface tissues need time to heal, and patients are asked to take 1 week off work (as compared with 48 hours for intra-LASIK), but final visual results are just as good as LASIK or intra-LASIK.

Surface laser procedures take about 10 minutes for each eye. Anesthetic drops are applied to the eye to make the operation painless. The eyes are typically sore and light sensitive for 3-4 days after surgery, and drops and special contact lenses are used to minimise discomfort during this period.

There is a limit to how much corneal tissue you can safely remove in refractive surgery. So lens implantation techniques are generally preferred for the correction of higher refractive errors.

Cataract surgery involves replacement of the natural lens with an artificial lens implant. The power of this lens can be selected to suit your refractive requirements, and modern cataract surgery is about as accurate and as safe as LASIK for refractive correction. When the natural lens is not cloudy (a cloudy natural lens is a cataract), the operation is termed refractive lens exchange. It is commonly offered to people with high levels of long or short sight.

We do offer the most modern type of articial lens implants the so called “premium lenses” in RLE and cataract surgery for patients who are keen on higher level of spectacles independence (IOL = Intra Ocular Lens) such as multifocal lenses (to allow good distance and near vision), toric multifocal lenses ( to allow good near and distance vision in high astigmatic patients) , and toric lenses (to correct high degree of corneal astigmatism). Please note that those lenses are not without side effect. For example multifocal lenses are associated with increased risks of glare and haloes at night and therefore you will be counseled on the suitability of the premium lenses in your specific case.

Your suitability for any of the above premium implants and their side effects will be discussed in details during your appointment with your Consultants at Moorfields private.

Early cataracts are common in patients over 45, and cataract surgery is commonly preferred to LASIK in this age group.

Refractive lens exchange is a day case procedure, and is most commonly performed under local anaesthetic. The operation is not painful and good vision normally returns within 2 days of the surgery. Only one eye is operated on at a time, and typically the eyes are treated 3 days apart.

For younger patients with a clear natural lens and refractive errors outside the safe range for laser techniques, or abnormal corneas where laser surgery is contraindicated due to higher risks of long term complications the implantation of a second added on artificial lens is often preferable to cataract surgery or RLE. The second lens is situated just in front of the natural lens, acting a little like a contact lens within the eye.

 Phakic lenses can be implanted either one eye at a time or both eyes can be treated in one surgical session. The most common lenses used are the ICL or Veriflex phakic lenses.  The key advantage for this technique in patients under 45 years old is that natural, unaided reading vision is preserved. As with CLE, only one eye is operated on at a time. 

Before you can definitely be classed as suitable for refractive surgery at Moorfields Private, you will need to be seen by one of our consultants.

However, if you fit all the following criteria, it is likely that you will be suitable for corrective surgery:

• You must be over 21 and in general good health;
• You must have had a stable prescription for at least 12 months;
• Both eyes must have good vision;

And you should have a prescription within the recommended safe range for the procedure. For LASIK this is –1.00 to –10.00 (short sight) or +1.00 to +4.00 (long sight) including any astigmatism. Higher refractive errors are more difficult to eliminate completely with laser but can however usually be corrected by lens implantation. Ask your optometrist if you are not sure how to interpret your prescription.

You may not be suitable if:

• You are pregnant or breast-feeding;
• You have had a previous Herpes Simplex (viral) infection of the cornea;
• You are taking any drugs which interfere with the healing response (for example, drugs used during chemotherapy);
• One or both eyes has a significant ocular abnormality or keratoconus (conical cornea);
• You have severe dry eye disease;
• You have worn contact lenses within 1 week (soft lenses), 4 weeks (gas permeable hard lenses), or 6 weeks (conventional hard lenses) of the assessment - contact lens wear can cause temporary changes in your corneal shape making accurate assessment difficult. Therefore most consultants may ask you to leave your contact lenses out prior to your pre-operative assessment; the practice manager will let you know when you book your appointment.
• If you have certain medical conditions, such as diabetes, SLE, rheumatoid arthritis, any connective tissue disorder or other auto-immune disease, you will need to be assessed carefully for suitability.

Your prescription for glasses or contact lenses is a series of numbers in different boxes. Here’s an example:

The above prescription refers to someone with moderate short sight with mild astigmatism.

OD refers to your RIGHT eye prescription; OS to your LEFT.

The SPH (sphere) box shows how long- or short-sighted you are, measured in dioptres (D). The CYL (cylinder) box shows the strength of any astigmatism, also measured in dioptres. The AXIS box shows the position of the astigmatism on the eye, which is measured in degrees (°). The degrees sign is omitted to avoid any possible confusion with zero.

SHORT SIGHT (myopia) is shown with a minus (-) sign, either before or above the value, in the SPH box.

LONG SIGHT (hypermetropia or hyperopia) is shown with a plus (+) sign, either before or above the value, in the SPH box.

ASTIGMATISM can be plus (+) or minus (-), and this is shown in the CYL box.

Remember that the final decision about your suitability for laser refractive treatment will always be made by an experienced Moorfields Private consultant who has examined your eyes thoroughly. We believe that it is very important that all patients are seen by the treating surgeon in advance of the surgery (i.e. not only on the day of surgery) and that the surgeon then undertakes all of the necessary post-operative visits to ensure continuity of care.

Your peace of mind

Understanding the risks involved in refractive surgery is very important. Your consultant will be able to comment in detail about any particular aspects of risk that might affect you.

Moorfields Private treats many patients each year who feel nervous about laser vision correction. We understand that these procedures need to be discussed fully with patients. Prior to your initial consultation, our surgeons provide comprehensive information packs detailing the risks and benefits of each of the surgical procedures we perform. It is extremely helpful if prospective patients read these documents prior to their consultation.

Although the risks in modern refractive surgery are minimal and very well understood, no procedure is risk free, and each has a defined set of risks. These should always be measured against the risk of infection due to wearing contact lenses. Even spectacles are not 100% safe (consider using spectacles for certain sports).

LASIK COMPLICATIONS
Three factors have made refractive surgery safer since initial results were published in the mid 1990s:

• the technology has improved;
• suitability for treatment is better defined; and
• Better corrective treatments are available for patients that are unlucky enough to experience problems.

Moorfields Eye Hospital is an international referral centre. If problems occur, our consultants are experienced in putting them right. With a patient approach and the right treatment, most complications can be corrected so that the final visual result is not affected.

Dry eyes
Some patients experience dryness in the first few months after LASIK. This is because the nerves to the front of the eye, which stimulate a normal blink rate and normal tear production have to regrow after treatment. This takes up to a year. Artificial tear drops are often helpful in this period, but continued long-term use is unusual in patients who did not have dry eye problems before surgery.

Glare and halo effects
These effects whilst night driving are commonly observed after LASIK. They tend to be most prominent in the early postoperative period, and are more likely to affect people with higher corrections and large pupils (usually young patients). These symptoms are rarely severe, and as with any dry eye feelings, will typically resolve within a year of surgery (night vision and halo effects have been almost eliminated with the advent of wavefront-guided intra-LASIK since the treatment area can be matched to the size of the pupil).

Loss of vision
Significant loss of vision is now extremely rare after LASIK. In a survey of 1000 consecutive cases treated at Moorfields Eye Hospital, no-one with corrected vision better than the driving standard before surgery ended up with corrected vision worse than this level afterwards. Patients with complications still attained a good visual result. The risk of losing vision after LASIK or surface laser treatments is probably similar to the risk of visual loss associated with a 5-10 year period of contact lens wear. There are no reported cases of complete loss of sight after either LASIK or PRK.

Keratectasia
Excessive thinning of the eye wall can cause the shape and focusing power of the eye to become unstable after treatment. This is rare, and careful screening to detect pre-existing corneal abnormalities, conservative limits on treatment, and pre-operative measurement of corneal thickness all combine to limit this risk.

Implant based refractive surgery (RLE and ICL surgery) complications
The risks for clear lens extraction are the same as for cataract surgery. Cataract surgery is now a very safe operation.

Overall, less than 1 in 2000 patients can have a complication that will permanently damage the eyesight in the operated eye.  This is usually the result of infection or bleeding in the eye.

Around 1 in 100 patients requires a second corrective operation after problems in the original procedure.
Around 1 in 10 patients requires a one-off, minor (YAG) laser procedure to correct a gradual deterioration in vision caused by a healing response in the tissues encasing the lens implant.

Retinal detachment
Patients with high levels of short sight are at particular risk of developing this sight-threatening problem. The risk of developing a retinal detachment within 10 years after cataract surgery or RLE is approximately 10%. Without surgery the risk is approximately 5%. It is not clear whether cataract extraction simply precipitates a detachment that would have occurred eventually anyway, or whether there is a genuine increased lifetime risk. 9 out of 10 retinal detachments are successfully repaired at the first attempt. Whether or not you opt for surgical correction of high levels of short sight, if you experience a sudden change in your vision, particularly a new shower of floating shadows, flashing lights in your eye, or a curtain coming across your visual field, you should always attend an eye department for an emergency examination. Catching retinal detachments at an early stage will improve the chances of successful surgery and overall retinal detachment surgery has a success rate of around 95%).

ICL surgery
The risk of serious permanent visual loss associated with ICL surgery is similar or smaller to that for RLE (< 1/2000).

Revision surgery is required in approximately 1 in 50 patients. The main additional risks are cataract and raised pressure in the eye (acute glaucoma).

Contact between the natural lens and the ICL may, in some cases, cause the natural lens to lose clarity. If lens opacification progresses to interfere with vision, the cloudy lens is called a cataract. Recent studies suggest that the chances of developing a cataract within 2 years of ICL surgery are less than 1%. ICL removal can be combined easily with cataract surgery in which a new artificial lens, equivalent in focusing power to the ICL, is implanted to take the place of the natural lens. Good distance vision is normally maintained.
Painful blockage of fluid flow within the eye (glaucoma) has been reported in 4% of cases immediately after ICL surgery, but this problem can be avoided by performing an intra-operative peripheral iridectomy.

The risk of severe infection and retinal detachment after ICL surgery appears to be lower than that of cataract surgery or RLE.

Why choose Moorfields Private?
Our refractive specialists are NHS consultants in ophthalmology, and have completed at least 8 years of training. They are also Fellows of The Royal College of Ophthalmologists, and have experience of a wide range of eye diseases and regularly perform microsurgical procedures (e.g. cataract and corneal surgery).

At Moorfields Private we also place a high value on continuity of care. The consultant who carries out your initial consultation will look after you before, during and after surgery.

 Many of our patients find the reassurance of having laser vision correction at one of the world’s leading specialist eye hospitals enables them to get over any nervousness they might have about these well-established and safe procedures. Since there are 8 consultants working in this field at Moorfields there will always be a doctor to look after you even if your regular surgeon is away. Moorfields also has a 24 hour ‘walk-in’ service to ensure that you will always have access to the care that you might (rarely) need.

When you are treated at Moorfields Private, there will always be a fully trained ophthalmic nurse assisting the consultant. Our equipment is state of the art – manufacturers are very keen to install their machines in our hospital because of our unique reputation – and our surgeons are assisted by a qualified, dedicated team of nurses, optometrists and technicians.

Moorfields Private puts patient peace of mind before everything else.

Where does Moorfields Private perform laser vision correction?
All laser refractive surgery treatment is carried out in our brand new Laser Suite on the private 4thfloor (Cumberlege Wing) of Moorfields Eye Hospital, City Road. Those patients who require lens exchange procedures (or similar) are admitted as day-cases to the same private floor.

Is the procedure painful?
No, the LASIK procedure is relatively painless. Although you will be awake during the surgery, your eye will be completely anaesthetized with eye drops. There may be some irritation when the anesthetic wears off. This typically only lasts for 3 - 4 hours. Discomfort lasts 3 - 4 days after surface laser procedures (PRK, LASEK) but drops and temporary soft contact lenses are prescribed to help with this.

Visual recovery is also a little slower. While functional, it takes around 1 week to fully recover (although both intra-LASIK and LASEK take around 2-3 months to finally stabilise).

Most patients only report mild discomfort after RLE and ICL surgery. This is usually brief and easily relieved by mild painkillers such as paracetemol.
  
How quickly can I go back to work?
This depends on your job and the environment you work in. Office work is usually possible the day after LASIK, and work will not damage your eyes provided that you are able to administer your after care drops on time. Surface laser procedures (PRK, LASEK) typically require a week off work. Implant based procedures (RLE and ICL implantation) usually require about 1-3 days for the vision to stabilise but most patients can drive and return to work after 48 hours. 
 
When can I start playing sports and other activities?
Playing sports (apart from contact sports) is safe after one week, and patients can fly within a few days. We would advise you to refrain from playing any contact sports or swimming for one month.
 
Can I have both eyes treated on the same day?
Laser corrective surgery is almost always carried out on both eyes simultaneously. Other types of corrective surgery, such as lens replacement and ICL surgery are carried out on one eye at a time with at least five days between each procedure.
 
Will I still need glasses after surgery?
Around a third of patients still require glasses for some distance purposes (for example, night driving) after LASIK.

A reasonable aim for refractive surgery is to attain distance vision at the normal level for a non-spectacle wearer. This should allow you to drive, socialise, watch television and play sport without glasses, but some patients still prefer spectacles for a limited range of activities such as night driving. Repeat treatment is performed in around 5% of patients to improve upon the initial result, and is more common where the initial treatment was for a high or more complex correction.

Presbyopia (the natural weakening of the 'focusing' muscles in the eye which occurs in people over the age of 45) is not corrected by laser or implant based surgery. But compromise strategies, in which one eye is focused primarily for good distance vision and the other is focused at arm’s length (monovision), are often very helpful in minimising spectacle dependence for near vision in later life.

You do not need a referral to see a Moorfields Private consultant. If you know which consultant you would like to see, please contact their private secretary or call the laser referral line on 020 7566 2299 to make an appointment or receive further information, or email us at enquiries@moorfields-private.co.uk