Refractive Lens Exchange
(Lens Replacement Surgery) in Essex

The natural lens sits just behind the pupil. From the mid-forties onwards it gradually loses its flexibility, which is why close work becomes harder. This is called presbyopia, and it happens to everybody.

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During refractive lens exchange the natural lens is removed through an opening in the front of the eye about 2 mm across, and an artificial lens is placed inside the same capsule that held it. The opening is small enough to seal itself without stitches.

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Each eye takes around fifteen to twenty minutes. Patients are awake, but the eye is fully numbed, so the sensation is of pressure and bright light rather than pain. Surgery is a day case.

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Because an artificial lens does not become cloudy in the way a natural lens does, a cataract can never develop in that eye afterwards. The thin natural membrane that holds the implant in place can still turn cloudy, which is common and easily treated with laser capsulotomy treatment. This is explained under Risks below.

Refractive lens exchange is usually considered from the age of 50, and is most suited to patients aged 55 and over. By 55 the natural lens has generally stopped contributing any useful focusing ability, so little is lost by replacing it, and the natural jelly inside the eye has usually separated from the retina, which lowers the risk of retinal detachment afterwards.

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Between 50 and 55 the operation can be appropriate, but the balance of benefit and risk needs careful individual assessment.

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In rare cases the operation is performed for patients as young as 45. This is normally where there is a strong additional reason, such as a degree of long sight that laser treatment cannot correct safely, an unusually shallow eye at risk of raised pressure, or early clouding of the natural lens. It is not offered simply because a patient in their forties would prefer not to wear reading glasses.

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Below 45 the natural lens is still doing useful work and other options are almost always better.

• Substantially less dependence on glasses for most patients, with the degree depending on the type of lens implanted.

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• A permanent result. The implant is designed to last a lifetime and does not need replacing.

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• No future cataract surgery. The operation being performed now is the one that would otherwise have been needed decades later.

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• A stable result. Unlike laser treatment of the cornea, the outcome is not gradually undone by continued ageing of the natural lens, because that lens has been removed.

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• Quick recovery. Most patients return to desk work within two to three days, and to driving within about a week once the legal vision standard is met.

The operation works best when it solves more than one problem at once. The strongest candidates are:

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Patients aged 55 and over

The natural lens has usually ceased to be useful, and the eye is more forgiving of the surgery.

Long-sighted (hypermetropic) patients

Long-sighted eyes tend to be shorter, which makes this operation safer, and strong long sight is one of the hardest prescriptions for laser to correct durably. This group is consistently among the most satisfied.

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Highly short-sighted (myopic) patients aged over 55

For patients who have worn strong glasses or contact lenses for decades, lens replacement can be transformative. Very high prescriptions are often beyond the safe range of laser treatment, contact lens tolerance tends to decline with age, and the natural lens in a very short-sighted eye frequently begins to cloud earlier than average.

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However, not every highly short-sighted eye carries the same risk. Two factors matter:

• Eye length. Very long eyes, generally those above about 26 mm, have a thinner and more fragile retina and a significantly higher lifetime risk of retinal detachment after lens surgery.

• Whether the jelly inside the eye has separated. With age, the gel that fills the eye (the vitreous) normally peels away from the retina, a change called posterior vitreous detachment or PVD. This is harmless and happens to everyone eventually, and once it has happened the risk of retinal detachment after lens surgery falls considerably. In an eye where it has not yet occurred, the risk is meaningfully higher.

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A highly short-sighted patient with a very long eye and no posterior vitreous detachment may be advised against the operation, or advised that the risk is several times that of an average eye. Both the length of the eye and the state of the vitreous are checked at assessment, and risks are discussed before any decision is made. Retinal detachment can lead to loss of vision, so this risk is not taken lightly.

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Patients already showing early lens changes

Where the natural lens has begun to lose clarity, replacing it treats a genuine problem rather than a preference.

Patients unsuitable for laser

Where prescription, corneal shape or eye anatomy rule out laser vision correction, lens replacement may be the only route to reduced glasses dependence.

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Patients with realistic expectations

Those who understand they are trading some glasses use for some visual side effects do well. Those expecting perfection do not.

A significant proportion of people who request this operation are advised against it. Replacing a healthy natural lens is irreversible, and it should only be done where the benefit clearly outweighs the risk. Every lens replacement surgery carries a small risk of worse vision and the need for further surgery.

The operation is usually not advised for:

• Patients under 45, whose natural lens still focuses usefully.

• Patients in their late forties with good distance vision. Where only reading glasses are needed, there is a great deal to lose and comparatively little to gain. Laser blended vision is usually the better option.

• Very long, highly short-sighted eyes where the vitreous has not yet separated, because of the raised risk of retinal detachment described above.

• Patients with other eye conditions. Glaucoma with visual field loss, macular disease, previous retinal detachment, corneal conditions such as keratoconus, or a history of inflammation inside the eye all shift the balance, and some rule the operation out.

• Patients whose prescription is still changing, or who have untreated significant dry eye.

• Patients who could not accept wearing glasses for any task. No implant gives perfect vision at every distance in every light.

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Where the assessment shows the operation is not advisable, this is explained at the consultation along with the recommended alternative.

Lens replacement is not the only way to reduce dependence on glasses. Laser vision correction, implantable contact lenses, monovision contact lenses, varifocals and simply waiting are all reasonable options depending on age, prescription and the health of the eye. For most patients under 50, laser is the better starting point.

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A full comparison is set out here: Laser Eye Surgery or Lens Replacement.

There is no single best lens. The right choice depends on the health and measurements of the eye, on daily visual demands, and on what a patient is willing to trade.

Full-range lenses (trifocals) offer the best prospect of managing without glasses for distance, screen and reading. In exchange, almost everyone notices rings or starbursts around lights at night, especially in the first few months. For most these fade into the background; for a minority they remain a nuisance. These lenses require very healthy eyes and a regular corneal surface. Detailed measurements at assessment determine whether an eye is suitable.

Extended-range (EDOF) lenses give sharp distance and good arm’s-length vision with fewer night-time effects, but glasses are usually still wanted for small print or reading in poor light.

Single-focus lenses, sometimes with a small deliberate difference between the two eyes, give the best quality of vision, particularly at night. Reading glasses will be needed. This may be the recommended option where other eye conditions are present.

The measurements taken at assessment sometimes rule out the lens a patient had hoped for. Where that is the case it is explained clearly, with the reason.

Both approaches are offered, and the choice is discussed at the consultation.

Sequential surgery, with the eyes operated on separately, usually about a month apart. The interval allows the first eye to settle completely and allows the result of the first eye to inform the lens power chosen for the second. 

Same-day surgery on both eyes, known as immediate sequential bilateral surgery. Each eye is treated as a completely separate operation, with fresh instruments, fresh fluids, fresh gloves and a fresh set of implants, so that nothing passes between them. The advantages are a single visit, a single recovery period, one course of time away from work, and a faster return to balanced vision without a period of one eye being corrected and the other not. The trade-offs are that the second eye’s lens power cannot be refined using the first eye’s result, that both eyes are blurred for the first day or two so more help is needed at home, and that in the very rare event of a complication both eyes could be affected at once.

Same-day surgery suits patients with straightforward, well-matched eyes, no other eye disease, and practical reasons to minimise time away from work or travel. 

Every operation carries risk. The following are the ones that matter.

Not reaching the target prescription
Published studies of lens surgery report that around 85 per cent of eyes finish within half a dioptre of the planned result, which usually means good unaided vision without glasses. For the small minority of patients who are unhappy with their post-operative refractive outcome, there is the option of adjustment using refractive laser surgery. This may require an additional fee. Achieving the correct lens power or refractive outcome is more challenging in patients who have had previous laser refractive surgery. These patients are therefore more likely to need glasses following surgery.

Night-time visual effects
Halos, glare and starbursts around lights, most noticeable when driving after dark are common with premium lenses, especially trifocals. They usually improve over three to six months as the brain adapts. In a small minority, roughly one in ten to one in twenty, they remain troublesome. Very rarely, around one in a hundred, the implant is exchanged for a different type.

Clouding of the membrane behind the implant
A cataract cannot come back. The thin natural membrane that holds the implant in place, however, frequently turns cloudy in the months or years afterwards, which blurs the vision again. It is corrected in a couple of minutes with a painless laser in clinic, and once treated it does not return. There is an additional charge for this treatment.

It is needed more often, and sooner, after premium lenses, because even slight clouding affects them more than it affects a single-focus (monofocal) lens. Published figures put the rate at around one in twenty for single-focus lenses within the first few years, and around one in five for premium lenses within the first year. Younger patients are more likely to need it than older ones.

Retinal detachment
The most serious of the common risks, because it threatens sight and can occur years after surgery. In an average-length eye the lifetime risk is low, (under one in a hundred). In a long, highly short-sighted eye, particularly where the vitreous has not separated, it can be significantly higher. 

Any sudden shower of floaters, flashing lights, or a shadow moving across the vision requires same-day assessment, however long after surgery it occurs.

Infection inside the eye
This is a rare, but potentially sight-threatening complication. It occurs in approximately one in one thousand to one in three thousand and is treated as an emergency.

Swelling at the back of the eye
Fluid (cystoid macular oedema) can cause blurring some weeks after surgery and usually settles with drops.
 

Permanent loss of focusing ability
Once the natural lens is removed it cannot be replaced. Any remaining ability to change focus is lost. This is the point that most warrants careful thought in patients under 55.

Dry eye
Common in the first few months and usually manageable with drops.

Assessment. A full examination with the pupils dilated, detailed scans of the front and back of both eyes, and precise measurement of the length and shape of each eye. These determine whether surgery is advisable, which lens is suitable, and what the individual risk of retinal detachment is. Patients should not drive themselves home. Contact lens wearers should leave soft lenses out for two weeks and rigid lenses for four weeks beforehand, as they alter the shape of the cornea and would make the measurements inaccurate. Please bring copies of your glasses prescriptions from the past two to three years, so that stability can be confirmed.
 

Deciding. There is no pressure to decide on the day. Surgery is arranged only once you are certain.

The day of surgery. Allow around two hours for one eye, and longer where both eyes are treated on the same day. A responsible adult must take the patient home, and should remain with them overnight after same-day bilateral surgery.

Afterwards. Vision is usually usable the following day and improves over two to four weeks. Drops are used for four weeks. Swimming and eye rubbing should be avoided for two weeks. Review takes place one to four weeks after surgery, and often again once the eye has settled.

Self-pay fees start around £3,500-4000 per eye for a single-focus lens, and from £4500-5000 per eye for a premium lens. This includes the surgery and post-operative follow-up. The initial consultation is charged separately at £250.

See pricing section of the website for up to date fees.

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Refractive lens exchange is an elective procedure and is not usually covered by private medical insurance, unlike cataract surgery. 

Mr Alex Baneke is a Consultant Ophthalmic Surgeon at Mid and South Essex NHS Foundation Trust, specialising in cataract, lens replacement and glaucoma surgery, with private clinics in Southend and Brentwood. He holds a fellowship from Moorfields Eye Hospital. GMC number 7169631.

Every assessment and every operation is carried out by Mr Baneke personally.

The first step is a full assessment to establish whether lens replacement is appropriate and, if so, which lens suits the eye. Where it is not appropriate, this is explained along with the recommended alternative.