Cataract surgery

16 min read


Cataract surgery is a common procedure used to treat cataracts that are affecting your daily activities.

What are cataracts?

are cloudy patches in the lens (the transparent structure at the front of the eye) which can make vision blurred or misty and can develop in one or both eyes.

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 is affected.

In most cases, a cataract will continue to develop and surgery to remove the category is the only way to restore vision.

Read information about

when cataract surgery is used

The operation

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 the operation.

The procedure lasts 30-45 minutes and vision is improved almost immediately.

If you have cataracts in both eyes, surgery will be carried out on separate occasions. This gives the first eye time to heal and your vision time to return.

Read more information about

how cataract surgery is performed


results of cataract surgery
may depend on which type of lens is fitted. Most people will need to wear glasses for either near or distance vision, or both. However, once lenses have been fitted, about 95% of people will find their vision returns to how it was before the cataracts appeared.

Getting back to normal

You will be able to go home as soon as the effects of the anaesthetic have worn off. You'll have to arrange for someone to take care of you for the first 24 hours after surgery.

Take it easy for the first two or three days after the operation and make sure to use any eye drops you are given by the hospital.

Other recommendations include:

  • try not to touch or rub your eye
  • keep soap and shampoo out of your eyes
  • do not swim for two weeks after surgery
  • avoid playing sports where there is a risk that you may get knocked in the eye for around two weeks

Read more information about

recovering from cataract surgery

Are there any risks?

Cataract surgery is common and associated risks are low. However, there are more risks involved with cataract surgery in children and people with certain conditions such as:

  • advanced
  • diabetic retinopathy
  • severe
  • someone who has ever taken alpha receptor antagonist tablets

The most common complication is a condition called posterior capsule opacification (PCO) which causes cloudy vision to return. If you develop PCO, you may need laser eye surgery to correct it.

Other complications are much rarer and include:

  • infection in the eye
  • inflammation (swelling and redness) in the eye
  • tearing of the lens capsule
  • retinal detachment
  • inability to remove all of the cataract

Most people find cataract surgery is successful and are happy with the results. However, any of these complications may lead to loss of vision or pain and may require further surgery.

Read more information about the

risks of cataract surgery


Cataract surgery is very common and the associated risks are very low, but can be serious.

The Royal National Institute of Blind and Partially Sighted People (RNIB) estimates that less than 2% of people experience any serious complications that require further 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 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 cells growing over the back of the artificial lens.

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

If you develop PCO, you may need another operation to correct it 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 or stitches are necessary, you should be able to return to your normal activities straight away.

Other complications

Other possible complications of cataract surgery are much rarer but can 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)
  • retinal detachment
  • inability to remove all of the cataract

You should seek immediate medical attention if you experience sudden loss of sight or increasing pain after cataract surgery.

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

It is usually possible to successfully treat 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 rare.

Cystoid macular oedema

One possible complication that can cause loss of vision is cystoid macular

. 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 other treatments is continuing.

Childhood cataract surgery

More risks are 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 (PCO))
  • 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.

Wearing glasses

The natural lens in your eye can change shape. This is how it enables your eye to focus on objects both near to you and further away.

Fixed strength (monofocal) and multifocal replacement plastic lenses cannot do this. Therefore, after cataract surgery, you may also need reading glasses or glasses for distance vision.

One review of a number of studies found that 95% of people with a monofocal lens and 68% of people with a multifocal lens needed glasses after having cataract surgery.

Another type of artificial lens, called an accommodating lens, aims to allow the eye to focus on both near and distant objects.

The National Institute of Health and Clinical Excellence (NICE) has reported some evidence that this type of lens improves clearness of vision. However, more evidence is needed to confirm this lens improves accommodation (how the lens adapts to focus images). NICE also noted this area of technology is changing rapidly, and it is not yet fully understood how these lenses work.

Read the NICE guidance on the use of accommodating replacement plastic lenses and multifocal lenses.

How it is performed

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 as day surgery under

local anaesthetic
, which means you can go home afterwards. Nearly all of your vision will return within two days of surgery but you will need someone to look after you for the first 24 hours after surgery. Read more about
recovering from cataract surgery

Pre-operative assessment

Before your operation, you will be referred to a specialist eye doctor (an ophthalmologist or ophthalmic surgeon). They will assess your eyes and general health.

During the assessment, your eyes are measured to prepare for the artificial lens that will replace your natural lens.


Cataract surgery is very common and can often be completed within 45 minutes.

Phacoemulsification is the most common cataract procedure and usually takes 15-30 minutes.

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

When the entire cataract has been removed, the surgeon inserts a small plastic lens through the incision in your cornea. The lens sits in the lens capsule, behind the pupil. The replacement lens is folded in half when it's inserted so 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.

Replacement lenses

When the cloudy lens is removed 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


Following cataract surgery, you can go home once you have recovered from the effects of the local anaesthetic (painkilling medication).

Arrange for someone to collect and take you home as you will not be allowed to drive. You may find wearing sunglasses or a hat when you leave hospital helpful because your eye could be sensitive to sunlight.

Also arrange for someone to take care of you for the first 24 hours after surgery. This is because full vision may take up to two days to return, though sensation usually returns to the eye within a few hours. Complete healing may take several months.

Follow up

Your ophthalmologist or a nurse will give you eye drops to help the eye heal and prevent infection.

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.

Side effects

Side effects of cataract surgery are usually temporary. They can 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

It is also common to experience more

than normal after cataract surgery. They should settle down a week or two after surgery.

However, floaters can be a symptom of posterior vitreous detachment (PVD), a common condition that often occurs naturally with age. PVD does not usually cause any long-term problems with your vision but there is a small risk it can lead to

retinal detachment

See your opthalmologist if you begin to experience the following symptoms at a later date:

  • a sudden increase in the number or size of floaters
  • flashes of light
  • blurred vision
  • a dark 'curtain' moving across your vision

Recovering at home

Take it easy for the first two or three days after the operation. Continue to use the eye drops that you have been given as instructed, usually for about a month. New glasses can also usually be prescribed after about a month.

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

, should ease mild pain.


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.

You should:

  • try not to touch or rub your eye
  • keep soap and shampoo out of your eyes
  • do not wear eye make up for one week after surgery
  • do not swim for two weeks after surgery
  • 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.

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.


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 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 in 100 people 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 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 given monofocal lenses.

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

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

Glasses prescription

It will take several weeks after 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.

When it should be done

If you have a cataract getting in the way of your daily activities and affecting your ability to drive or read, you may need cataract surgery.

Typical early signs of cataracts are:

  • blurred vision or dazzle from lights (such as oncoming car headlights)
  • increasing
    short sightedness
  • colours becoming duller

In the past, people with cataracts were encouraged to wait until they could hardly see. These days, surgery to remove a cataract can be done at any stage of development, once it is affecting your ability to function.

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

  • macular degeneration
    – a painless eye condition that leads to gradual loss of central vision (the ability to see directly in front of you)
  • diabetic retinopathy – a complication of
    where part of the eye becomes progressively damaged
  • angle closure

Alternatives to surgery

The first signs of a cataract 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 minor cataract. It does not become more difficult to remove a cataract should you decide to wait before having surgery.

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

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.