Laser Eye Surgery Guide

Laser eye surgery is a vision correction procedure which, for many people, has become an increasingly popular choice. It is seen as a convenient way of correcting eyesight problems without the hassle of glasses or contact lenses. Glasses and contact lenses are useful ways of correcting vision problems and have successfully done so for a great many years. However, some people find that they are awkward, inconvenient or fiddly and would prefer a long lasting solution. What laser eye surgery can do is to eliminate the need for these corrective devices and so give you near perfect vision. You may have heard of the terms ‘lasik’ or ‘lasek’ and wonder what these mean. They are the medical names given to the two main types of laser surgery although there are a number of variations within these types. They both reshape the cornea (the front of the eye) in exactly the same way: the difference is in the preparation of the eye for surgery.

How do lasers treat short sightedness and other eyesight problems?

They aim to change the focusing power of the eye in the following refractive errors:

  • Short-sightedness (myopia): the aim is to flatten the cornea which the laser does by removing tissue from the centre of the cornea.
  • Long-sightedness (hypermetropia/hyperopia): tissue is removed from the edge of the cornea which will result in a curved shaped cornea.
  • Astigmatism: with this condition the cornea has to be reshaped from a ‘rugby ball’ shape (oval) to a normal ‘football’ (rounded’ shape.

Lasek and Lasik along with other types of laser eye surgery are discussed in more detail throughout this site. Visit each of the individual procedure pages, which are also in an FAQS style, to learn more about that procedure. You will find that some procedures are more popular than others.

How does Laser Eye Surgery work?

Laser eye surgery is surgery undertaken to correct an eyesight problem such as short-sightedness, long-sightedness or astigmatism. These problems are known as ‘refractive errors’.

The cornea (the clear part at the front of the eye) is responsible for the eye’s ability to focus upon an object. This along with the iris enables us to see objects clearly – both close up and at a distance.

However, the shape of the cornea can affect this ability. A change in its shape can result in problems with seeing objects at a distance (short-sightedness) or close up (long-sightedness). There is also the problem in which the cornea sees some parts of an object clearly and yet other parts are distorted (astigmatism).

Our genetics are responsible for the focusing power of our eyes.

Laser eye surgery is a relatively quick and painless procedure in which the cornea is reshaped to correct a refractive error. The cornea has a thin, protective outer layer called the ‘epithelium’ which is moved to one side to allow the laser to do its reshaping.

Local anaesthetic drops are placed in the eye before the start of treatment. The laser then reshapes the cornea according to the type of refractive error.

The whole procedure takes around 20 minutes at the most.

Everyone is different which means that there is no single procedure that works for every person. Some people may find that lasek works better for them; others are suited to prk or lasik.

What are the different types of laser eye surgery?

There are a range of different procedures for the correction of eyesight problems. These include the following:

  • LASIK (LASer In situ Keratomileusis)
  • LASEK (LASer Epithelial Keratomileusis)
  • EpiLASEK (as above)
  • PRK (Photo-Refractive Keratectomy)
  • LTK (Laser ThermoKeratoplasty)
  • RK (Radial Keratotomy)
  • AK (Arcuate Keratotomy)
  • ICR (IntraCorneal Rings)
  • CK (Conductive Keratoplasty)
  • IOL (Intra-Ocular Lens)
  • ICL (Implantable Contact Lenses)
  • Cross-Linking CR3
  • Blended Vision

Am I suitable for laser eye surgery?

This will be decided during the consultation between you and the surgeon (ophthalmologist).

In general, you need to be aged 21 or over with healthy eyes, have a stable prescription (no change in the preceding 2 years) and in good health. You also need to have realistic expectations about this surgery.

Laser eye surgery tends to work best for those patients with minor or moderate eyesight problems. If you have what is termed a ‘strong prescription’ (severe refractive error) then laser surgery may not be an option.

In this case the surgeon may recommend Implantable Contact Lenses (ICL) instead.

Who is not suitable for laser eye surgery?

Unfortunately, not everyone is suitable for laser eye surgery. If you have a medical condition such as rheumatoid arthritis or an eye disease such as glaucoma then surgery may not be advisable.

If you are taking a prescription medicine such as oral steroids then you may not be suitable for this procedure.

If you are pregnant then you will find that the surgeon will not perform surgery until after childbirth. Why? Hormones can affect eyesight during pregnancy which means it would be very difficult to measure the eye or to obtain an accurate prescription.

And if you are breastfeeding then you will be asked to wait for 3 months after this period to enable your eyes to return to normal.

Other conditions which may rule you out include having large sized pupils with a high correction measurement (noted on your prescription), epilepsy, MS and increased internal eye pressure. Plus people who have a difficulty finding suitable glasses, are obsessive or suffering from depression.

Basically if you are healthy and wear glasses or contact lenses with no reported problems then laser eye surgery is an option.

I have a strong prescription; can I still have laser eye surgery?

This will decided upon by the surgeon. He or she will have a set of criteria and a treatment range which includes measurements in ‘dioptres’.

If your prescription falls outside of this range then you will not be considered for surgery.

The surgeon wants to be sure that you will benefit from this procedure and that there will be no unwanted side effects or complications with your vision. If you consider how precious your eyes are then the last thing you will want to do is to take any chances with them.

If you are advised against surgery then there will usually be a very good reason for this.

However, he or she will recommend several alternatives such as Implantable Contact Lenses (ICL) or Clear Lens Exchange (CLE).

Is there an age limit?

The lower age limit is set at 21 as the eyes will have fully matured by then. However, surgery has been carried out on patients as young as 18 although this will have been in exceptional circumstances.

Older patients

There are special considerations for those patients aged 50 and over. The eye muscles do stiffen after the age of 45 as a result of the ageing process. As a result of this ‘presbyopia’ or the need for reading glasses occurs.

In these cases the patient has to decide between good distance vision (post surgery) and good close up vision.

Why is this?

At present, there is no laser eye correction for presbyopia: plus the stiffening of the eye muscles will continue as a result of ageing.
So, once you reach your forties you will find it more difficult to read a book or newspaper. This means buying a pair of reading glasses for this purpose.

Your ability to see objects at a distance is not affected unless you are long-sighted.

If you are short-sighted then you are at an advantage. Laser surgery can be performed to correct your distance vision; all you have to do if you want to see objects close to you is to remove your reading glasses.
There is a procedure called ‘Monovision’ for this very purpose. It involves the patient undergoing laser vision surgery upon the ‘dominant eye’ (the stronger eye) to correct problems with distance vision.

The other eye is kept slightly short-sighted and is used to see objects close at hand.

The patient becomes used to this after a few months and will find that they are able to view objects at all distances without the need for corrective lenses.

Another option is a treatment called ‘CK’: this is also known as ‘reading glasses treatment’ and doesn’t require a laser. It is
non-surgical in the sense that tissue is not removed during the procedure unlike laser treatment.

Visit our ‘CK’ FAQS section for more information about this.

Other options include Implantable Contact Lenses (IOL), Clear Lens Exchange (CLE) and Cataract Surgery.

Is there an alternative?

If you are not suitable for laser eye surgery then don’t be downhearted: there are several alternatives which can give very good results.

These are:

  • CK: Conductive Keratoplasty
  • ICL: Implantable Contact Lenses
  • CS: Cataract Surgery.
  • C3-R: Cross-Linking C3-R.
  • Blended Vision: a laser treatment for presbyopia.

These are all tried and tested techniques which can improve your vision.

What are the benefits of laser eye surgery?

The main benefits are improved vision and freedom from wearing glasses or contact lenses (in some cases).

Success in laser eye surgery is measured in terms of achieving ‘driving standard’ vision or the ability to read the 5th line on an eyesight chart (10:20).

Those patients with a mild refractive error tend to get the best outcome from this treatment. Moderate to severe refractive errors can still achieve a good outcome although patients with these errors may still have to wear glasses or contact lenses.

Patients aged 45 upwards will require reading glasses after this treatment – if they have had both eyes operated on.