Refractive lens exchange (RLE) (also known as Added Value Cataract Surgery, or PRELEX (Presbyopic Lens Exchange)) is refractive surgical procedure in its own right.

Here the natural crystalline lens of the eye is removed and replaced with an artificial lens implant, which maybe monofocal, Light adjustable lens, multifocal or accommodative, in order to correct errors in refraction. RLE is fundamentally the same as cataract surgery, other than your natural lens is still clear and in cataracts this lens becomes cloudy. RLE is performed primarily to change the refractive properties of the eye, to enable good clear vision without the use of spectacle correction.

How Does RLE Work?

In hyperopic or myopic (nearsighted) patients, the light coming into the eye from outside does not focus properly on the retina. Often this is due to the eye being too long (as in myopia) or too short (as in hypermetropia). This prevents the natural lens from producing the fine focus required to focus the image on the central part of the retina. RLE, aims to correct this focusing anomaly by removing the eye's natural lens and replacing it with an artificial lens, with the aim of allowing the person's vision to be focused and reducing spectacle dependence. The artifical lens placed within the eye is selected on a patient to patient basis to achieve the best individual outcomes. This is underaken following measurements of your eyes, called biometry.  However, once in the eye the power cannot be changed with the majority of lenses.  This, however, is possible with the Light Adjustable Lens. The Royal College of ophthalmologists data suggests that only a small proportion of lens inmplanted actually achieve the desired outcome (

To achieve that excellent level of vision, 20-20 Vision offers the Light adjustable Lens, which is the only lens in the world which can assure the best chance of achieving 20-20 vision in 95% of patients by doing what it says, allowing adjustment whilst in the eye.  This is similar trying several different lense in glasses, except whe a lens is in the eye, you only really have 1 chance to get things right.


Who are candidates for RLE?

  • Persons with refractive error in their middle ages or older hyperopic people
  • Persons with presbyopic symptoms
  • 21 years of age or older: younger people may still have eyes that are growing.
  • Persons not suitable for laser refractive surgery.
  • Dissatisfied or intolerant of glasses or contact lenses.
  • Have had no change in glasses or contact lens prescription for at least a year.
  • Be willing to accept a small amount of risk associated with surgery.
  • Persons who understand that glasses and/or contacts are occasionally still needed for some activities after surgery, dependent on lifestyle needs.


Is 20/20 vision guaranteed with RLE?

RLE surgery is an extremely advanced technology for surgical vision correction. The eye can be measured very precisely using a technique called biometry to ensure an accurate as possible lens implant is selected.  However, there are inherent errors in calculations, so it is impossible to provide any guarenteed outcomes.  Remember, this is a surgical procedure and as such carries potentially visually threatening risks.  Your surgeon, however, will have under taken thousands of lens procedures and will be registered with the General Medical Council and hold full UK accreditation and of course, be highly skilled in performing the procedure. As such, the vast majority of people undergoing RLE surgery are very happy with their post-procedure vision.

It is difficult to ever guarantee 20-20 vision, but we can say with confidence that almost 95% will achieve this with the Light Adjustable Lens, as long as there are no other medical conditions of your eye that prevent the best level of vision. LASIK or PRK may sometimes be used after RLE to "touch up" any residual refractive error in those opting for other lens implants. On occasion, however, glasses or contacts will still be needed for some viewing situations after RLE surgery.


What are the risks of RLE surgery?

  • These are essentially the same as for cataract surgery.
  • Posterior capsule opacification is the commonest postoperative complication.

If you have been affected by any of the symptoms mentioned above, please don't hesitate to give us a call.

We have a team of experts on stand-by who are ready to take your call at our Manchester (0161 907 2685) Clinic or our Blackpool (01253 308 031) Clinic.