Is there a Prescription Limit for Laser Eye Surgery?

Many people think that the numbers on their prescription are enough to determine their suitability for Laser Eye Surgery – but the reality is often much more complicated.

Of course, your prescription plays a significant role in your eligibility for treatment, but many factors affect your suitability for Laser Eye Surgery.

The process of Laser Eye Surgery – as well as the limits for treatment – have changed significantly in recent years. This means that Laser Eye Surgery is now an effective option for more people than ever before, often even individuals with high prescriptions who may have once been deemed unsuitable candidates.

But it is still important to understand the limits of Laser Eye Surgery. With that in mind, we’re taking a closer look at the current prescription limits for three of the most common refractive errors: myopia (short-sightedness), hyperopia (long-sightedness), and astigmatism.

The Prescription Limits for Myopia

Myopia – also known as short- or near-sightedness – is the most common refractive error globally. Moreover, ongoing studies indicate that this error is becoming increasingly widespread with current estimates suggesting that around half of the global population will be short-sighted by 2050.

Short-sightedness is characterised by having difficulties distinguishing objects at a distance, while near objects are clear. For example, myopic patients may struggle to read road or street signs without the help of visual aids.

Myopia is indicated on your prescription with a minus (-) dioptre value (D). A dioptre is the unit of measurement used to represent the amount of correction required to achieve clear vision.

Lower Limit for Treatment

The prescription range for treating myopia with LASIK (the most common Laser Eye Surgery procedure) typically falls in the range of -0.5 D to -8.0 D myopia. Patients with a myopia prescription below -0.5D rarely require vision correction, so Laser Eye Surgery is generally not recommended unless the patient also has some degree of astigmatism.

Upper Limit for Treatment

The upper prescription limit for Laser Eye Surgery treatment is less easy to define due to significant differences in capabilities between clinics. For example, most clinics can treat patients with moderate to severe myopia up to about -8.0D. However, patients with more severe short-sightedness will also need to have thick and healthy corneas as their treatment will require the removal of more corneal tissue.

Some clinics (including London Vision Clinic) are often able to treat patients outside of this range. This is thanks to having access to the latest technology and the capability to perform the latest procedures. For example, the ReLEx SMILE procedure allows surgeons to treat patients with thinner corneas and even prescriptions beyond -10.0D!

The Prescription Limits for Hyperopia

Hyperopia – also known as long- or far-sightedness or hypermetropia – is less common than myopia; however, it is still estimated to affect around a quarter of the global population.

It is characterised by a difficulty in distinguishing and focusing on objects that are close up in your field of vision. As patients with hyperopia often have to strain in order to perform close-up tasks – such as reading or working at a computer – the error is also associated with headaches and fatigue.

Hyperopia is different from the kind of far-sightedness we begin to experience as we get older (presbyopia) as it can affect people of all ages. While these two errors involve many of the same symptoms, they require a different approach for correction.

Hyperopia is measured in plus/positive (+) dioptres. As with myopia, most clinics do not perform Laser Eye Surgery for the treatment of very mild hyperopia (i.e., prescriptions lower than +1.0 D), unless there is also some degree of astigmatism.

At most Laser Eye Surgery clinics, the limit for treating hyperopia with LASIK is around +3.0 – +4.0 D. Again, many clinics are unable to treat patients with a hyperopic prescription beyond this limit as they don’t have access to the latest technology to do so safely. At London Vision Clinic, our access to the leading technology and expertise allows us to treat patients with a hyperopic prescription up to +7.0 D.

The Prescription Limits for Astigmatism

Astigmatism is a refractive error that occurs when the eyeballs or cornea is abnormally shaped. For example, while healthy eyes are spherical, like a football, astigmatic eyes may be shaped more like a rugby ball. This error affects how light is directed into the eye and focused on the retina, causing blurry vision, eye strain, and headaches.

While most people have some degree of astigmatism, it is usually unnoticeable and does not require correction. Astigmatism often occurs alongside both myopia and hyperopia and is represented alongside these values in your prescription. The severity of astigmatism is shown on your prescription card in positive and negative dioptres.

Laser Eye Surgery can typically treat astigmatism up to around 6.0 D, whether it appears alone or alongside other refractive errors. However, again, this can vary from clinic to clinic.

Astigmatism requires correction in more than one plane which means it can be more complex to treat when compared to other refractive errors. But with the right technology and level of expertise, virtually all astigmatism symptoms are treatable – even for high prescriptions.

Discover Your Suitability Today

The bottom line is, that there is no clearly defined limit for treating refractive errors with Laser Eye Surgery. Your suitability will depend on a range of factors and can only be determined through a thorough consultation process. However, choosing an independent clinic with access to the latest technology and the best surgeons will give you the best chance of being found suitable for Laser Eye Surgery.

If you’d like to learn more about the Laser Eye Surgery process and suitability, get in touch with one of our friendly clinic coordinators or Book a Consultation today.