Limbal Relaxing Incisions are used to treat mild astigmatism. The surgeon cuts the cornea in certain areas that are too steeply curved, in order to flatten them to a more regular curve. Many people undergo AK in addition to other corrective eye surgery. However, AK is used less frequently now that excimer lasers are approved to correct astigmatism in procedures such as LASIK and PRK.

In one version of AK, known as Limbal Relaxing Incisions (LRI), the surgeon cuts an area of the eye's surface known as the limbus where the white and coloured areas of the eye meet, well away from the central part of the cornea. This forces the cornea to become more rounded when it heals, rather than retaining the rugby ball shape that causes astigmatism.

Phakic intraocular lenses are implantation devices that can treat near and far sightedness. They are usually considered when laser treatment is deemed unsuitable. During the procedure (depending on type of lens used), the surgeon attaches the lens to the iris or places it behind the iris and in front of the eye's natural lens. Unlike regular contact lenses, you cannot feel the lenses and they do not require any maintenance. This surgery is reversible should complications occur.

IOLs have been around for several decades and are normally implanted during cataract surgery. They replace the eye's natural lens, which has become cloudy (a cataract) and is removed by the surgeon.

IOLs were originally only available as fixed focal length lenses to provide good distance vision. Cataract patients would still require spectacle lenses to help with intermediate and close-up vision after the surgery.

But a new generation of IOLs are now available that give good vision at near, intermediate, and distance ranges. The need for glasses is therefore greatly reduced.

This new IOL technology is no longer limited to cataract patients. IOLs are now available for correction of myopia, hyperopia, and/or presbyopia (presbyopia is the inability of the eye to focus at close distances, first noticed with ageing when fine print starts to blur).

In certain circumstances eye surgeons will recommend exchanging a patient's healthy natural lens for an artificial lens or IOL as the best way of providing vision correction.

PRELEX is the surgical procedure that replaces the natural lens of your eye, with an intra-ocular lens implant.

CK uses mild heat from radio waves to shrink collagen in the periphery of the cornea. This steepens the cornea overall. It is usually used to correct presbyopia, the inability of the eye to focus at short distances. The procedure takes about 5 minutes.

* Not offered at Aston University Day Hospital