- Refractive lens exchange (RLE) is suitable for patients who are already in the reading glasses age group that wish to gain greater independence from glasses.
- Lens clarity and flexibility diminish with age, and many older patients who would like their sight corrected actually have the beginnings of a cataract. Replacing the natural lens is often therefore the best option for sight correction, even for patients with a lower spectacle prescription, particularly if they are longsighted. When cataract surgery is performed primarily to correct the need for glasses, it is called RLE.
- RLE and cataract surgery are exactly the same operation. The surgery is normally performed under local anaesthetic, and you can go home straight after surgery. Recovery is quick, aftercare is simple, and there are few restrictions on activity after surgery. You can normally work or fly from the next day. Surgery is normally performed on one eye at a time, with the two operations typically one week apart.
- Multifocal lens implant options are available to aid reading vision and provide greater spectacle freedom.
In all forms of eye surgery, problems can occur during the operation or afterwards in the healing period. Problems can result in permanent, serious loss of vision (vision worse than the driving standard in the affected eye that cannot be corrected with glasses or contact lenses).
More commonly, problems can be corrected with changes in medication or additional surgery. Typically, these additional operations feel like the original surgery and have a similar recovery period.
Loss of vision
Permanent, serious loss of vision is significantly more common after RLE than after laser vision correction or PIOL implantation, affecting approximately 1 in 500 patients. This may mean vision worse than the driving standard or, in some cases, complete loss of vision in the affected eye.
Permanent serious visual loss is typically caused by damage to the retina. This can result from infection or an inflammatory response after surgery, retinal detachment after surgery, or bleeding during surgery. Some problems occurring during surgery increase the risk of sight threatening problems afterwards. These include a common complication of surgery called posterior capsular rupture, (breakage of the membrane just behind the IOL).
The UK benchmark rate for capsule rupture for all cataract surgeons is just under 1.5%. Experienced surgeons have a lower rate, but all surgeons have at least some cases affected by posterior capsular rupture. It is not always possible to implant a multifocal IOL safely if posterior capsular rupture has occurred, and this may mean greater than anticipated reliance on glasses after surgery.
Second operations may be required to correct a complication from the initial surgery. This could include lens repositioning or exchange, surgery to retrieve lens fragments from the back of the eye, or retinal detachment repair. With or without RLE, retinal detachments are more common if you are very shortsighted; but the risk of retinal detachment is approximately five times higher in the first four years after cataract surgery or refractive lens exchange.
Statistical techniques (biometry formulae) and eye measurements (biometry) are used to guide selection of the IOL required to correct your vision. Limitations on the accuracy of these techniques mean that laser vision correction to fine tune the focus is sometimes required to touch up the visual result after RLE.
The commonest reason for visual deterioration after RLE is posterior capsule opacification (PCO). This is a gradual misting over of the membrane just behind the IOL, which affects many patients. PCO may occur months or years after surgery, and is normally treated successfully with a one-off minor laser procedure called YAG laser capsulotomy.
Risks of contact lens wear
Continuing in contact lenses is often the main alternative for people considering sight correction surgery. If you follow the right safety advice, contact lens wear is low risk; but approximately 1 in 3000 wearers each year will develop a serious corneal infection.
To minimise this risk, you should not swim or shower in contact lenses, and should not wash them in tap water. Sleeping in contact lenses, including those designed for overnight wear, increases the risk of infection significantly. Soft, daily disposable lenses are safer than non-disposable lenses.