Cataract surgery
Cataract surgery

Cataract surgery is a procedure used to treat cataracts, where changes in the lens of the eye cause cloudy, blurry, or misty vision.

It's the most common operation performed in the UK, with more than 300,000 procedures carried out each year.


Cataracts occur when changes in the lens of the eye cause it to become less transparent. The lens is the crystalline structure that sits just behind your pupil, which is the black circle in the centre of your eye.

When light enters your eye, it passes through the transparent layer of tissue at the front of the eye (the cornea) and the lens, which focuses it on the light-sensitive layer of cells at the back of your eye (the retina).

Cataracts sometimes start to develop in a person's lens as they get older (age-related cataracts), stopping some of the light reaching the retina. This can affect your vision, making it become increasingly cloudy, blurry, or misty.

Although cataracts are often associated with age, in rare cases babies are born with cataracts or young children can develop them (childhood cataracts).

This topic focuses on surgery for adults with cataracts.

When is cataract surgery recommended?

Slight cloudiness of the lens is a normal part of ageing. Significant cloudiness, or cataracts, usually get slowly worse over time. Surgery to remove them is the only way to restore vision.

However, surgery isn't necessary if your vision isn't significantly affected and you don't have difficulties carrying out everyday tasks.

Cataract surgery is available on the NHS if you're having difficulty with activities such as reading, driving, or looking after someone in your care.

Read more about when cataract surgery is carried out.

The operation

Cataract surgery is a relatively straightforward procedure that usually takes 30 to 45 minutes.

It's often carried out as day surgery under local anaesthetic, which means you'll be awake during the procedure and can go home on the same day.

During the operation, the surgeon will make a tiny cut (incision) in your eye so they can remove the affected lens. After it's been removed, a small plastic lens called an intraocular implant or intraocular lens will be inserted.

If you have cataracts in both eyes, you'll have two separate operations carried out a few weeks apart. This gives the first eye time to heal and time for your vision to return.

Read more about how cataract surgery is performed.

Getting back to normal

You'll normally be able to go home a few hours after having cataract surgery, but you'll need to arrange for someone to collect you and take you home.

Take it easy for the first two or three days after the operation and make sure you use any eye drops you're given while in hospital.

You can continue doing most of your normal activities after cataract surgery, although you'll need to avoid touching your eye or getting anything in it, such as soap and water, for a few weeks.

Read more about recovering from cataract surgery.

Results of cataract surgery

Most people's sight will improve soon after having cataract surgery, although your vision may be blurred for a few days.

Eventually, you should be able to:

  • see things in focus, although glasses are often needed
  • look towards lights without as much glare
  • tell the difference between colours, which will seem brighter

Most people need to wear glasses for near or distance vision – or both – after cataract surgery. This is because artificial lens implants can't focus on a range of different distances.

The surgeon will normally aim for more focused distance vision, with dependence on reading glasses for close up work, although this depends on the strength of your glasses and individual circumstances.

With glasses, most people have a good enough level of vision to be able to drive and carry out everyday activities without any problems.

Your vision may not be restored to normal if you also have another eye condition or in the rare event of a serious complication.

What are the risks and complications?

The risk of serious complications developing as a result of cataract surgery is small.

The most common complication is a condition called posterior capsule opacification (PCO), which can cause your vision to become cloudy again. In PCO, a skin or membrane grows over the back of the lens implant months or years later.

If necessary, PCO can be treated with a simple laser eye surgery procedure to cut away the membrane.

Other risks or complications of cataract surgery are much rarer and can include:

  • tearing of the lens capsule, the "pocket" that holds the lens in place
  • all or some of the cataract dropping into the back of the eye
  • inability to remove all of the cataract or insert a lens implant
  • infection or bleeding in the eye

Most complications that can potentially develop after cataract surgery can be treated with medication or further surgery, and don't usually have a long-term impact on your vision.

However, there's a very small risk – around 1 in 1,000 – of permanent sight loss in the treated eye as a direct result of the operation.

Read more about the risks of cataract surgery.

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When should it be done?

Cataract surgery is usually offered on the NHS if you have cataracts that are affecting your ability to carry out daily activities.

For example, surgery may be offered if problems with your vision are causing difficulties reading, driving, or looking after someone in your care.

In the past, people with cataracts were encouraged to wait until they could hardly see. However, these days surgery to remove a cataract can be carried out at any stage once your sight has been affected.

There are no national guidelines stating what your level of vision needs to be before cataract surgery is carried out, although individual Health Boards may have their own criteria outlining when cataract surgery should be offered.

In some cases, cataract surgery may be recommended if you have another eye condition, such as diabetic retinopathy, that can't be monitored or treated properly if you have cataracts.

Waiting to have surgery

Cataracts tend to get gradually worse over time, although it isn't possible to predict how quickly this will happen.

Most people with cataracts will need surgery eventually, but immediate treatment may not be necessary if your vision isn't significantly affected.

It doesn't become more difficult to remove a cataract if you decide to wait before having surgery.

If immediate treatment isn't necessary or you decide to wait before having surgery, other measures may be helpful in the meantime, such as:

  • new glasses
  • brighter lighting
  • anti-glare sunglasses
  • magnifying lenses

There are no medications, eye drops, or dietary supplements that have been proven to improve cataracts or stop them getting worse.

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How is it performed?

Before having cataract surgery, you'll be referred to a specialist eye doctor (an ophthalmologist or ophthalmic surgeon) for an assessment.

The specialist will assess your eyes and general health, and check for any other eye conditions that may be affecting your vision.

A member of the eye care team will take measurements of your eyes to assess the strength of the artificial lens that will replace your natural lens.

This is also a good time to discuss the procedure in detail and ask any questions you may have.

If you have cataracts that affect your vision in both eyes, you'll need two separate operations, usually carried out 6 to 12 weeks apart.

This will give the first eye that's been treated time to heal and your vision time to return. It also allows the surgeon to know your new glasses prescription in the first eye.

The procedure

Cataract surgery is a common and relatively straightforward procedure that usually takes up to 30 to 45 minutes.

It's usually carried out as day surgery under local anaesthetic, which means you're conscious during the procedure and can go home on the same day.

The most common surgical technique used is known as phacoemulsification.

Before the operation, a nurse will put drops in your eye to widen (dilate) your pupil.

You'll also be given a local anaesthetic, which can be applied as eye drops or given as an injection into the tissue around your eye.

The surgeon will make a tiny cut in your cornea, the transparent layer of tissue at the front of your eye.

A small probe that emits ultrasound waves is inserted through your cornea into the eye to break the affected lens into pieces. The pieces are then liquified and sucked out. A second probe sucks out the remaining soft pieces of outer lens.

After the affected lens has been removed, the surgeon will insert a small plastic lens in its place.

The replacement lens is usually curled up in an injector and injected through the cut in the cornea. When it's in place, it unfolds itself and adopts the natural position of the old lens.

In a few cases, it may be necessary to make a slightly larger incision in the eye to replace the affected lens, which may need to be closed with tiny stitches that are removed a few weeks later.

Replacement lenses

After the cloudy lens has been removed, it will be replaced with an artificial clear plastic lens. The replacement lens is called an intraocular implant, or intraocular lens (IOL).

There are three types of IOL available. They are:

  • fixed strength (monofocal) lenses –which are set for one level of vision, usually distance vision; this type of lens is used in the majority of cataract operations
  • multifocal lenses – which can be set at two or more different strengths, such as near and distance vision
  • accommodating lenses – which allow the eye to focus on both near and distant objects in a similar way to a natural lens

Using multifocal or accommodating lenses can potentially reduce the chances of needing reading glasses after surgery, although most people will need to wear glasses in some situations after surgery regardless of the type of lenses they had fitted.

Multifocal and accommodating lenses aren't usually available on the NHS. If you would like multifocal or accommodating lenses, you may be able to have them by paying for cataract surgery privately.

After surgery

Most people are able to go home a few hours after having cataract surgery, although you'll need to arrange for someone to collect you and take you home. You'll usually have a pad over your eye when you go home.

It's also a good idea to arrange for someone to help look after you when you get home as you may feel out of sorts for 24 hours.

If the vision in your other eye is poor, you may struggle with your vision for the first few days as it settles down.

It's likely you'll experience some discomfort in and around your eye after the procedure, but this should improve within a few days.

Complications in the days and weeks after surgery are rare, but you should contact the hospital as soon as possible if you experience increasing pain or vision loss at any point.

Read more about recovering from cataract surgery and the risks of cataract surgery.

The ophthalmic team

If you have cataracts, a number of different healthcare professionals may be involved in your care:

  • optometrist – examines eyes, tests sight, and prescribes and dispenses glasses and contact lenses. They're trained to recognise eye conditions and sight defects. Most optometrists work in high-street opticians, while some work in hospitals.
  • ophthalmologist – a medical doctor who specialises in eye conditions and their treatment. They mainly work in hospitals and hospital eye departments.
  • dispensing optician – make up glasses from prescriptions provided by optometrists or ophthalmologists. They may also fit contact lenses, but don't carry out eye examinations.
  • orthoptist – specialises in problems relating to eye movement and the eyes working together, including squintlazy eye, and double vision.
  • ophthalmic nurse – a nurse who has developed skills in eye care. They work in hospital eye departments.
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You should be able to go home on the day you have cataract surgery, but you'll need to arrange for someone to collect you and take you home.

You'll probably have a pad and plastic shield over your eye when you leave hospital, which can usually be removed the following day.

However, you may be advised to wear the shield at night for the first week or so to stop you touching or rubbing your eye while you're asleep.

Feeling should start to return to your eye within a few hours of surgery, but it may take a few days for your vision to fully return.

You may find it useful to arrange for someone to help take care of you until your vision returns, particularly if the vision in your other eye is poor.

Before you leave hospital, you'll be given some eye drops to use for four weeks to help your eye heal and prevent infection. You'll be advised further about the use of eye drops at your follow-up appointment.

Recovering at home 

Take it easy for the first two or three days after having cataract surgery. Start using the eye drops after removing the eye shield the day after your operation, and continue to use them until you're advised you can stop – they'll usually be needed for four weeks.

After surgery, you'll probably experience:

  • mild pain in and around your eye
  • an itchy or sticky eye
  • blurred vision
  • a feeling of grittiness in your eye
  • a slight headache
  • bruising of the skin around the eye
  • discomfort when looking at bright lights

These side effects are completely normal and should improve within a few days.

Taking an over-the-counter painkiller, such as paracetamol or ibuprofen, will help reduce any pain. Wearing sunglasses may also help avoid any short-term discomfort caused by bright lights.

When to seek medical advice

Upon leaving hospital, you'll be given a 24-hour phone number to call if you have any problems. Seek medical advice as soon as possible if you experience:

  • a throbbing or severe pain in or around your eye
  • a severe frontal headache with or without nausea and vomiting
  • a sudden deterioration or loss of vision
  • increasing redness in your eye
  • the sudden appearance of black dots, specks or streaks in your field of vision (floaters) or flashes of light in your eye

These problems may be a sign of a complication of cataract surgery.


Your surgeon will advise you about any activities you need to avoid while recovering from your operation.

In most cases, you'll be able to be up and about, bathe, shower, and wash your face and hair. However, you should:

  • avoid strenuous activities, such as lifting heavy objects
  • avoid bending with your head below waist level for extended periods of time
  • avoid touching, rubbing or knocking your eye
  • keep soap and shampoo out of your eyes
  • avoid wearing eye make-up for one week
  • avoid swimming for two to four weeks
  • avoid sports and activities where there's a risk of your eye being knocked for two to four weeks

You can read and watch television almost immediately without doing any harm, although your vision may be blurry until your eye gets used to its new lens or you have new glasses fitted.

If you work, how soon you can return will largely depend on what your job involves. Most people can return after a few days, but you may need a few weeks off if your job involves strenuous activities or potential exposure to liquid or dust that could get into your eye.


Up to 90% of people who have cataract surgery will eventually have a good enough level of vision to start driving again if they don't have another eye condition.

The Driver and Vehicle Licensing Agency (DVLA) states you can start driving again if you can read a number plate 20 metres (about 65.5 feet) away with both eyes open.

Many people who have cataract surgery will need glasses to be able to do this, in which case you'll need to wait until your new glasses are fitted a few weeks after surgery.

If your vision is good in the other eye, you may be able to do this sooner, but in either case you also need to be confident doing an emergency stop.

Wearing glasses after cataract surgery

Most people will need to wear glasses for either long or short distance vision after cataract surgery, even if they didn't need to before the operation. This is because artificial lens implants can't focus on a range of different distances.

Natural lenses can do this in people under the age of 50, but this ability is gradually lost with age, so most people require reading glasses before surgery anyway.

A review of a number of studies found 95% of people with a monofocal lens and about 70% of people with a multifocal lens needed glasses after having cataract surgery.

Another type of artificial lens called an accommodating lens is designed to act in a similar way to a natural lens. This should allow for a better range of focus after cataract surgery.

However, while there's evidence these lenses improve the range of focus, the National Institute for Health and Care Excellence (NICE) says more evidence is needed to be sure they improve how the lens adapts to focus images before they're made routinely available on the NHS.

Read the NICE guidance about the use of accommodating lenses and multifocal lenses.


When you're discharged from hospital after your cataract operation, you'll be told when to return for a follow-up appointment.

Follow-up arrangements vary, but may include a check by a nurse or optometrist after a week. You should also have another follow-up appointment four to six weeks after your operation, which may be at a high street optician.

During your appointment, an eye care professional will check your eye and tell you when you can stop using the eye drops.

If you need new glasses, you'll be told when you should visit an optometrist (optician) to have your eyes tested and glasses fitted.

It's usually necessary to wait several weeks for your vision to settle down before an optometrist can give you a new glasses prescription.

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The risk of serious complications as a result of cataract surgery is very low. Most common complications are treatable and don't have a long-term impact on your vision.

The risk of complications is higher in people with other eye conditions, such as uveitis, high myopia (severe short-sightedness) or diabetic retinopathy.

The risk of complications is also higher if you cannot lie flat easily, have problems breathing or are taking tablets for prostate problems.

Ask your eye surgeon (ophthalmologist) to explain the possible risks before your operation.

Cloudy vision

The main problem that can occur after cataract surgery is a condition called posterior capsule opacification (PCO).

This is where part of the lens capsule (the "pocket" that the lens sits inside) thickens, which can cause cloudy vision. This is not the cataract returning, but a skin or membrane growing over the back of the artificial lens.

Less than 10% of people who have cataract surgery will eventually develop PCO, usually within two years.

If you develop PCO and your vision is affected, you may need laser eye surgery (when laser light is used to cut through the membrane) to correct it. During this procedure, the cloudy part of the lens capsule will be removed, leaving enough of the capsule to hold the artificial lens in place.

Laser eye surgery for PCO is a short and relatively simple procedure that normally takes about 15 minutes. Your vision should either be improved immediately or within a few days and, as no surgical incisions or stitches are necessary, you should be able to return to your normal activities straight away.

Other complications

Other complications of cataract surgery are much less common, but can include those listed below.

During the operation:

  • inability to remove all of the cataract
  • tearing of the lens capsule
  • bleeding inside the eye
  • a bit of the cataract dropping into the back of the eye
  • damage to other parts of the eye, such as the cornea (the transparent outer layer of the eye)

After the operation:

  • inflammation (swelling and redness) in the eye
  • swelling of the retina (cystoid macular oedema) – where fluid builds up between layers of the retina at the back of the eye, sometimes affecting vision
  • swelling of the cornea – where fluid builds up in the cornea at the front of the eye; this usually clears itself
  • retinal detachment – a rare complication where the retina (layer of nerve cells inside the back of the eye) becomes separated from the inner wall of the eye
  • infection in the eye, such as endophthalmitis (a rare bacterial infection)

You should seek immediate medical advice if you experience any loss of vision or increasing pain or redness after cataract surgery.

It is usually possible to successfully treat complications that arise from cataract surgery with medication or further surgery. Rarely, your vision may be worse than it was before surgery or there may be permanent damage to your eye, causing a loss of sight.

However, the vast majority of people have a good result from surgery and are happy with the improvement in their vision.

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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 08/03/2016 10:36:42