Please seek medical advice about your laser eye surgery procedure

Eye prescriptions for glasses and contact lenses can change over time. There are several phases of life where this is more common. The first is in childhood as the eyeball grows. This usually stops by around age 18-21 but can continue into your 20s.

You should visit the optician every 12-24 months. If the prescription changes at sucessive visits, we say that the eye prescription is “unstable”. If we perform laser vision correction while the eye is still changing the results may not last.

This is why Moorfields Private surgeons need to see evidence of stability in your eye prescription before offering vision correction surgery. 

Some variation between spectacle tests is normal, but if there is a progressive increase in the amount of short sight, you may need to wait before having laser eye surgery. 

One of our specialist vision correction surgeons can review your prescription history and examine your eye to determine if you are a good candidate for laser eye surgery.

Laser eye surgery reshapes the cornea to correct the virsion and this process reduces the thickness of the cornea.

There is a limit to how much reshaping (and thinning) of the cornea can be done before it loses its shape and integrity. Therefore patients with very high prescriptions are not suitable for laser eye surgery.

The amount of laser treatment that can be safely applied depends on the thickness of your cornea to begin with, which varies quite a lot from person to person.

The approximate safe limits are:

• Around -8 to -10 dioptres for short-sightedness (myopia).
• Around +4 to +6 dioptres for hypermetropia.

Your surgeon will assess you and tell you whether your eye prescription falls within the safe treatment range for you.

For patients with high prescriptions, you may be suitable for alternative procedures such as implantable contact lenses or refractive lens exchange.

Patients with diabetes may be able to have laser eye surgery but poor diabetic control can mean you aren't suitable.

Our expert consultants advise to avoid laser eye surgery during pregnancy or whilst you are breastfeeding.

Laser eye surgery and other forms of permanent vision correction are not available to anyone under the age of 18. Patients who wish to have vision correction will need to wait until they are at least 18 to have laser eye surgery.