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Cataract surgery

Page last reviewed: 13/07/2011

Cataracts are cloudy patches in the lens (the transparent structure at the front of the eye). They can make vision blurred or misty and can develop in one or both eyes. One eye can often be more affected than the other. 

The lens

The lens is usually clear and allows light to pass through it to the back of the eye. However, if parts of the lens become cloudy (opaque), light is unable to pass through the cloudy patches.

Over time, the cloudy patches can become bigger and more of them can develop. As less light is able to pass through the lens, a person's vision is likely to become blurry or cloudy. The cloudier the lens becomes, the more a person's sight will be affected.

How common are cataracts?

Cataracts most commonly affect older people and are the leading cause of impaired vision throughout the world. It is estimated that over half of all people over 65 have some cataract development in one or both eyes.

Childhood cataracts are very rare, affecting about 3 in 10,000 children.


In most cases, a cataract will continue to develop and the only way to restore vision is by having surgery to remove the cataract. Cataract surgery is one of the most common and quickest forms of surgery. Many people are able to return to their usual daily routine 24 hours after having the operation.

The procedure to remove a cataract usually lasts 30-45 minutes, and vision is improved almost immediately. After cataract surgery, most people will need to wear glasses for either near or distance vision, or both. However, once these have been fitted, about 95% of people will have normal vision.



The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre).

Page last reviewed: 13/07/2011

If you have a cataract that is getting in the way of your daily activities and affecting your ability to drive or read, you may need to have cataract surgery. Typical signs are blurred vision or dazzle from lights (such as oncoming car headlights).

In the past, people with cataracts were encouraged to wait until the condition was so bad that they could hardly see. However, now surgery to remove a cataract can be done at any stage of development.

Your GP may recommend that you have cataract surgery if you are at risk of developing another eye condition, such as:

  • macular degeneration, a painless eye condition that leads to the gradual loss of central vision (the ability to see what is directly in front of you)
  • diabetic retinopathy, a complication of diabetes (a long-term condition that is caused by too much glucose in the blood) where part of the eye becomes progressively damaged

Alternatives to surgery

The first signs of a cataract, such as a slight blur at the edge of an image, may be helped with:

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

However, these will not stop the cataract growing and blurring your vision. There is no medication that can clear a cloudy lens.

Not having surgery

If your cataract is not interfering with your daily life, you may decide not to have the operation straight away. It is safe to leave a cataract. It does not become more difficult to remove a cataract should you decide to wait a while before having surgery.

However, without surgery, your lens will gradually become so cloudy that you will not be able to see any detail at all, although some light will always be distinguishable.


The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre).

Page last reviewed: 13/07/2011

Cataracts are removed using surgery. If you have cataracts in both eyes, you will have surgery on them on separate occasions. This gives the first eye time to heal and your vision time to return.

Most cataract operations are performed using keyhole surgery, which means that only a very small incision (cut) is made. The surgery is usually performed as day surgery, which means you can go home afterwards. You will need someone to look after you for the first 24 hours after surgery.

Pre-operative assessment

Before your operation, your GP or the optometrist who diagnosed your condition will refer you to a specialist eye doctor (an ophthalmologist or ophthalmic surgeon). They will assess your eyes and general health. This is called a preoperative assessment.

During the assessment, your eyes will be measured. These measurements will be used to prepare for the artificial lens that will replace your natural lens. An appointment will probably be made for your operation to take place in a separate visit.


There are three types of cataract surgery:

  • phacoemulsification
  • extracapsular cataract surgery
  • intracapsular cataract surgery

Nowadays, cataract surgery is very common and can often be completed within 45 minutes. Phacoemulsification usually takes 15-30 minutes, although extracapsular and intracapsular operations can take longer.

The different types of surgery are explained in more detail below.


Phacoemulsification is the most common cataract procedure.

During phacoemulsification, your surgeon will put drops in your eye to dilate (widen) your pupil (the black circle at the centre of your eye). You will also be given a local anaesthetic (painkilling medication), which can be applied as eye drops or given as an injection into the tissue around the eye.

The surgeon will make a tiny incision (cut) in your cornea (the transparent outer layer on the front of your eye). A small probe will be inserted into your cornea that releases ultrasound waves (high-frequency sound waves) to break up the cataract into tiny pieces. After the ultrasound probe has been removed, a new probe will be inserted that will suck out the cataract.

Once the entire cataract has gone, the surgeon will insert a small plastic lens through the incision in your cornea. The lens sits in the lens capsule (a little 'pocket') behind the pupil. The replacement lens is folded in half when it is inserted so that it can fit through the incision in the cornea. When it is in place, it unfolds itself and adopts the natural position of the old lens.

Extracapsular cataract surgery

If your ophthalmologist (eye surgeon) thinks that your lens is too awkward to remove by phacoemulsification, they may suggest extracapsular extraction.

For some surgeons, extracapsular extraction, also known as extracapsular cataract extraction (ECCE), is the preferred method of cataract removal.

During the procedure, your ophthalmologist will make a larger incision (cut) in the cornea and through to the lens capsule to remove the whole lens in one piece. Once the lens has been removed, an artificial lens, similar to those used in phacoemulsification, is inserted into the lens capsule.

Intracapsular cataract surgery

Intracapsular cataract surgery is very rarely carried out, but is sometimes needed if the ligaments that support the lens (zonules) are too weak. The procedure is also known as intracapsular cataract extraction (ICCE).

ICCE involves removing the entire lens, including the lens capsule. An artificial, plastic lens is inserted through the incision (cut) and is positioned so that it sits over the pupil.

Replacement lenses

When the cloudy lens is removed during cataract surgery, it is replaced with an artificial, clear, plastic lens. This is called an intraocular implant, or intraocular lens (IOL).

Three types of IOL are available. Your ophthalmologist will help you to decide which type of lens will be best for you. The three types of lens are:

  • fixed strength lenses (monofocal), which are set for one level of vision, usually distance vision
  • multifocal lenses, which allow 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 the natural human lens

The cornea is the clear outer layer at the front of the eyeball that acts as a window to the eye.

An incision is a cut made in the body with a surgical instrument during an operation.

The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre).

An ophthalmologist is a medical doctor who specialises in eye disease and its treatment or surgery. They mainly work in hospitals and hospital eye departments.

An optometrist (ophthalmic optician) examines eyes and tests sight. They can prescribe glasses and contact lenses, and are trained to recognise sight defects and eye diseases.

Meet the ophthalmic team

  • An optometrist examines eyes, tests sight and prescribes and dispenses spectacles and contact lenses. Optometrists are trained to recognise eye conditions and sight defects. 
  • An ophthalmic medical practitioner (OMP) is a medical doctor who specialises in eye care. They examine the eyes, test sight, diagnose abnormalities and prescribe corrective lenses. 
  • An ophthalmologist is a medical doctor who specialises in eye conditions and their treatment. They mainly work in hospitals and hospital eye departments. 
  • A dispensing optician fits prescriptions for spectacles provided by optometrists, OMPs or ophthalmologists. They may also fit contact lenses. A dispensing optician does not carry out eye examinations. 
  • An orthoptist specialises in problems relating to eye movement and the eyes working together, including squint, lazy eye and double vision. 
  • An ophthalmic nurse is a nurse who has developed skills in eye care. Ophthalmic nurses work in hospital eye departments.

Page last reviewed: 13/07/2011

Cataract surgery is very common and the associated risks are very low. The Royal National Institute of Blind and Partially Sighted People (RNIB) in the UK estimates that less than 2% of people experience any serious complications after having cataract surgery.

However, ask your eye surgeon (ophthalmologist) to explain the possible risks before your operation. If a severe cataract is not treated, it is possible that the loss of sight may be permanent.

Cloudy vision

The most common risk associated with cataract surgery is developing a condition called posterior capsule opacification (PCO). This is where part of the lens capsule (the 'pocket' that the lens sits inside) thickens and causes cloudy vision. This is not the cataract returning, but is due to cells growing over the back of the artificial lens.

PCO is very common, affecting the vision of up to half of all people who have cataract surgery. PCO usually develops between six months and five years after the operation.

One review of a number of studies has suggested that replacement lenses with rounded edges have been linked to a larger number of PCO cases. Therefore, replacement lenses with sharp edges are preferred in cataract surgery. It is still not clear whether the material that the replacement lens is made of makes any difference to cases of PCO. 

If you develop PCO, you may need to have another operation to correct it. This will be done using laser eye surgery (when energy beams are used to cut through part of the eye). During laser eye surgery, the cloudy part of the lens capsule will be removed, with enough of the lens being left to hold the artificial lens in place.

The procedure should only take around 15 minutes, and your vision should either be improved immediately or within a few days. As no surgical incisions (cuts) or stitches are necessary, you should be able to return to your normal activities straight away.    

Complications of cataract surgery

Possible complications of cataract surgery include:

  • infection in the eye
  • bleeding in the eye
  • inflammation (swelling and redness) in the eye
  • tearing of the lens capsule
  • 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)

The College of Optometrists has estimated that, in most cases, the risk of complications occurring during cataract surgery is less than 1 in 100. The most common complication is tearing of the lens capsule, which may occur more frequently than this.  

It is usually possible to successfully treat any complications that arise from cataract surgery. Occasionally, 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, this is very rare.

Cystoid macular oedema

One possible complication that can cause loss of vision is cystoid macular oedema. This is where fluid builds up between layers of the retina (the layer of nerve cells that lines the inside of the back of the eye).

There are two different types of cystoid macular oedema:

  • angiographic cystoid macular oedema
  • clinical cystoid macular oedema

Angiographic cystoid macular oedema is very common, but does not affect vision. Clinical cystoid macular oedema can cause vision loss and is thought to make up between 0.1% and 12% of cases.

Cystoid macular oedema may be treated with non-steroidal anti-inflammatory drugs (NSAIDs), although research into this is continuing.

Childhood cataract surgery

There are slightly more risks involved with childhood cataract surgery. They include:

  • glaucoma (increased pressure inside the eye that affects vision)  
  • squint (strabismus), where one eye turns inwards, outwards, upwards or downwards while the other eye looks forwards
  • abnormalities that affect the pupil (the black circle at the centre of each eye)
  • vision becoming cloudy again (visual axis opacification or posterior capsule opacification, see above)
  • retinal detachment, when the retina (the layer of nerve cells inside the back of the eye) becomes separated from the inner wall of the eye
  • infection, such as endophthalmitis (a rare bacterial infection)

If childhood cataracts are not treated, the child may become blind. Even if the cataracts are removed, visual impairment or blindness can remain.

An incision is a cut made in the body with a surgical instrument during an operation.

Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.

The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre).

An ophthalmologist is a medical doctor who specialises in eye disease and its treatment or surgery. They mainly work in hospitals and hospital eye departments.

The retina is the nerve tissue lining the back of the eye, which senses light and colour and sends it to the brain as electrical impulses.

Page last reviewed: 13/07/2011

After the operation

Following cataract surgery:

  • Your eye may be covered with a pad or a piece of tape, which you can take off after a few hours or the following day.
  • Your ophthalmologist (a medical doctor who specialises in eye conditions and their treatment) or a nurse will give you eye drops to help prevent infection and promote healing.
  • You can go home once you have made a full recovery from the anaesthetic (painkilling medication).
  • Arrange for someone to collect you and take you home as you will not be allowed to drive. Also arrange for someone to take care of you for the first 24 hours after surgery.
  • Sensation usually returns to the eye within a few hours and your vision should be improved after a few days. Complete healing may take several months.
  • You will be given a 24-hour phone number to call if you have any problems and a date for a follow-up appointment. Most ophthalmologists see the people they have treated one to three weeks after the operation.
  • You may find that wearing sunglasses or a hat when you leave hospital is helpful because your eye could be sensitive to sunlight.

Recovering at home 

On returning home after having cataract surgery:

  • Take it easy for the first two or three days after the operation.
  • Try not to touch or rub your eye.
  • Keep soap and shampoo out of your eyes.
  • In the past, the advice was not to bend after surgery, but this is no longer the case. You can bend, carry shopping, wash your face and hair, and generally carry on with life as normal.
  • It is best not to swim for two weeks after surgery. When you do, wear goggles. You should be able to swim without goggles after four weeks.
  • Avoid playing sports where there is a risk that you may get knocked in the eye, such as tennis, for around two weeks.
  • You should be able to read and watch television almost immediately if you have reading glasses, but your vision may be blurry as your healing eye gets used to its new lens. You may have to get new reading glasses.
  • If you experience more than mild pain or loss of vision, or if your eye starts to go red, contact your hospital for advice. Painkillers, such as paracetamol, should ease mild pain.
  • You can drive again when you can read a number plate 20.5m (67ft) away. You may have to get new glasses to be able to do this.
  • Continue to use the eye drops that you have been given as instructed, usually for about a month.
  • New glasses can usually be prescribed after about a month.

The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre).

An ophthalmologist is a medical doctor who specialises in eye disease and its treatment or surgery. They mainly work in hospitals and hospital eye departments.



If you have cataracts, it could affect your ability to drive. It is important that you inform your doctor and the Road Safety Authority (RSA) about a medical condition that could have an impact on your driving ability.

Side effects

The side effects of cataract surgery are usually temporary. They include:

  • an itchy or sticky eye and blurry vision for a few days after the operation
  • your eye may feel gritty for a few days
  • your eye may look red for a few days 
  • a slight ache, which should pass after a few days
  • bruising of the eyelid or eye, which will usually heal within a week

Page last reviewed: 13/07/2011

The sight of most people (around 95%) will improve almost immediately after cataract surgery. However, cataract surgery will not always completely restore your vision.

After the operation, if you do not have any other eye conditions, you should be able to:

  • see things in focus, although you may still need glasses
  • look into bright light without as much glare
  • tell the difference between colours
  • start to enjoy your usual activities, such as reading, working, watching television, sport and driving

Approximately 1 person in 100 will need to have a second operation. One person in 1,000 will experience a complication that results in them having permanently worse vision, even when wearing glasses.

Success of replacement lens 

Treatment for cataracts usually involves surgery to replace the clouded natural lens with an artificial monofocal lens, which has just one strength of focus. A monofocal lens will usually restore good distance vision, but you may still need to wear reading glasses for close work.

Sometimes, the natural lens is replaced with either a multifocal lens or an accommodating lens, which allows you to focus on both near and distant objects.

Some patients who have a multifocal lens fitted may not need to wear glasses at all after surgery. A review of studies by the National Institute for Health and Clinical Excellence (NICE) showed that 68% of patients who had multifocal lenses implanted needed glasses after their operation, compared with 95% of patients who were given monofocal lenses.

For any lens replacement, the quality of your vision after having cataract surgery depends on the correct measurements of your eye being taken before your operation.

The pre-operative assessment ensures that the most appropriate replacement lens is chosen to fit your eye, and it reduces your chances of having poor vision after your operation.

Glasses prescription

It will take several weeks after having cataract surgery for your vision to settle down before your optometrist (a person who examines eyes, tests sight and prescribes glasses and contact lenses) can give you a new glasses prescription, if you need one.

The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre).

An optometrist (ophthalmic optician) examines eyes and tests sight. They can prescribe glasses and contact lenses, and are trained to recognise sight defects and eye diseases.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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