Cataracts, age-related

Page last reviewed: 13/07/2011

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

The lens

The lens is normally clear and allows light to pass through 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 usually become bigger, and more of them develop. As less light is able to pass through the lens, the person's vision is likely to become blurry or cloudy. The cloudier the lens becomes, the more the person's sight will be affected.

How common are age-related cataracts?

Cataracts are the main cause of impaired vision in the world, particularly in developing countries. They affect men and women equally.

Cataracts most commonly affect older people. Cataracts that affect older people are known as age-related cataracts. In the UK, it is estimated that more than half of people who are over 65 years of age have some cataract development in one or both eyes.

Childhood cataracts

In rare cases, babies have cataracts when they are born, or children develop them at a young age. See the Health A-Z topic about Childhood cataracts for more information.

Outlook

If cataracts are mild, stronger glasses and brighter reading lights may enable people to live with the condition. However, if left untreated, cataracts can cause blindness.

Once cataracts start interfering with daily activities such as cooking or getting dressed, surgery is usually recommended. It is estimated that around 10 million cataract operations are performed around the world each year. Cataract operations are generally very successful with few complications.

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.

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

Page last reviewed: 13/07/2011

Cataract symptoms usually develop over a period of many years, and most commonly affect older people.

Over time, the lens (the transparent structure at the front of the eye) gradually becomes cloudy. If your cataracts are mild, you may not notice any symptoms to start with.

If you have cataracts in both eyes, one eye may be more affected than the other. Your vision may:

  • be blurred
  • be cloudy or misty
  • have small spots or dots on it (patches where your sight is not as clear)

Your sight may be affected by the light. For example, you may find it more difficult to see:

  • if the light is dim
  • when the light is bright, such as on a very sunny day, or in bright artificial light

Other ways that cataracts may affect your sight can include:

  • the glare from bright lights may be dazzling or uncomfortable to look at
  • colours may look faded or less clear
  • everything may have a yellowish tinge
  • reading, watching television and other daily activities may be more difficult than they used to be
  • you may have double vision (seeing two images of an object instead of one)
  • you may see a halo (a circle of light) around bright lights, such as car headlights or street lights
  • if you wear glasses, you may find that they have become less effective

The symptoms of cataracts can be similar to the symptoms of other eye conditions. Therefore, it is important to visit your GP or an optician (optometrist) for a check-up if you notice any changes to your vision.

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

Page last reviewed: 13/07/2011

The causes of age-related cataracts are unknown. Research suggests that some factors may increase the risk of cataracts developing.

Changes to the lens in the eye

As people grow older, changes can occur to the protein that makes up the lens (the transparent structure at the front of the eye).

Some experts think that this may be linked to how fluids and nutrients reach the eye. These changes in the lens protein can cause cloudy areas to develop. It is not known how or why getting older causes these changes to happen.

Risk factors

Research suggests that some factors may increase your risk of developing age-related cataracts. These include:

  • a history of cataracts in your family
  • smoking
  • lifestyle factors, such as poor diet
  • overexposing your eyes to sunlight
  • taking steroid medicines (medicines that contain powerful chemicals called hormones) for a long time

Other causes

In younger people, cataracts may have other less common causes. For example:

  • diabetes (a long-term condition caused by too much glucose in the blood, which can cause people to develop cataracts at an earlier age)
  • injuries to the eye
  • other eye conditions, such as uveitis (inflammation of the uveal tract in the eye)
Glossary
Lens
The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre of your eye).
Hormones
Hormones are groups of powerful chemicals that are produced by the body and have a wide range of effects.
Inflammation
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.

Page last reviewed: 13/07/2011

Eye examination

If you have problems with your vision, you should make an appointment to see your optician (also known as an optometrist). An optometrist can examine your eyes and test your sight. They are trained to recognise sight defects and eye conditions.

The optometrist may look at your eyes with an instrument called an ophthalmoscope. An ophthalmoscope has a light on the end that produces a magnified image of your eye. By shining a bright light into your eye, the ophthalmoscope enables the optometrist to look inside your eye.

If you have cataracts, your optometrist will be able to see them in your eye. They will also be able to see how much of your lens is affected.

Referral

In some cases, you may be referred to an ophthalmologist, or an ophthalmic surgeon, who will be able to confirm the diagnosis and plan your treatment. Ophthalmologists and ophthalmic surgeons are medical doctors who specialise in eye conditions and their treatment.

Sometimes, cataracts are diagnosed during a regular eye test, even if you have had no symptoms.

Glossary
Lens
The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre of your eye).
Optometrist
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.
Ophthalmoscope
A medical instrument with a light on the end that produces a magnified image of your eye.

Page last reviewed: 13/07/2011

Treatment for age-related cataracts may not be needed if:

  • you have no symptoms
  • your sight is only mildly affected

In the early stages of a cataract, your vision may be improved with stronger glasses, or by using a brighter light when you read, for example. However, the improvement may not last long.

Surgery is the only way to treat cataracts that become more severe.

When cataracts are treated

Your optometrist (a specialist who examines eyes and tests sight) or GP will probably recommend treatment if your loss of vision affects your usual daily activities. For example, if cataracts affect:

  • your ability to look after yourself or someone else
  • your driving
  • going out
  • seeing people's faces
  • your work
  • reading
  • watching television

Surgery

Cataracts are treated by having surgery to remove the cloudy lens in your eye. In most cases, the natural lens is replaced with an artificial, clear plastic lens. This is called an intraocular implant or intraocular lens (IOL).

Most cataract operations in Ireland are carried out under local anaesthetic, as keyhole surgery, where a very small incision (cut) is made. You will probably be admitted as a day patient (day case), which means that you will not need to stay in hospital overnight.

The most common cataract operation is called phacoemulsification, and is sometimes referred to as phaco extracapsular extraction. Cataracts cannot be treated with laser surgery (when beams of energy are used).

Before the operation

Before having cataract surgery, your GP or optician will refer you to an ophthalmologist or an ophthalmic surgeon (medical doctors who specialise in eye conditions and their treatment). They will assess your eyes and your general health. This is called a pre-operative assessment.

During the assessment, your eyes will be measured. The artificial lens that will replace your natural lens can then be prepared. An appointment will probably be made for your operation to take place during a separate visit.

Just before the operation, drops to dilate (widen) your pupil (the black circle in the middle of your eye) will be put into your eye. You will also be given a local anaesthetic that will prevent you feeling any pain during the procedure. This may be applied to your eye as drops, although sometimes an injection in the tissue around the eye may be used.

Once the anaesthetic takes effect, you will not be able to feel anything. While the operation is taking place, all you will be able to see is a bright light. You will not be able to see what is happening.

The replacement lens

Different types of replacement lens are available. These include:

  • 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

Your ophthalmologist will discuss with you which type of lens will suit you.

The operation

During the operation, your ophthalmologist will make a very small incision (cut) in the surface (cornea) at the front of your eye. Your ophthalmologist will then insert a tiny probe through this cut. The probe breaks up the cloudy lens into tiny pieces using ultrasound (high frequency sound waves). The tiny pieces will then be sucked out of your eye.

Once this is done, your ophthalmologist will insert an artificial, clear plastic lens through the incision. The lens sits in a little 'pocket' called the lens capsule to keep it in place. The lens is folded when it is inserted, and once it is in position it is allowed to unfold.

The operation usually takes 15 to 30 minutes, although sometimes it can take slightly longer. 

Other operations

Two other operations may be performed to remove age-related cataracts, although these are much less common. They are:

  • manual extracapsular extraction
  • intracapsular extraction

In manual extracapsular extraction, the ophthalmologist makes a slightly larger cut in the eye. The lens is removed in one piece, rather than being broken up by ultrasound.

During intracapsular extraction, the lens capsule is removed, as well as the lens. A replacement plastic lens is then sewn into the eye. In some cases, special (aphakic) glasses or contact lenses may need to be worn instead. Intracapsular extraction is rare in Ireland.

After your operation

The vision of most people who have cataract surgery improves almost immediately. However, it may take a little time to settle down completely. The incision (cut) in the eye's surface is so small that it usually heals by itself, although sometimes a small stitch may be needed.

Your ophthalmologist will probably advise you to take it easy, for example, by:

  • avoiding sports and any vigorous activities
  • not rubbing your eye
  • not getting soapy water in your eye, for example, while taking a shower
  • wearing a pad over your eye to protect it

When the operation has been completed, your plastic lens will be set up for a certain level of vision. After the operation, you may need to wear glasses in order to see objects that are:

  • far away (distance vision)
  • close to you (near vision)

If you wore glasses previously, your prescription will probably change. It will take several weeks after the operation for your vision to settle down before your optometrist can give you a new prescription.

Glossary
Lens
The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre of your eye).
Optometrist
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.
Incision
An incision is a cut made in the body with a surgical instrument during an operation.
Ophthalmologist
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.
Cornea
The cornea is the clear outer layer at the front of the eyeball that acts as a window to the eye.

Driving

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.

Page last reviewed: 13/07/2011

If most, or all, of the lens (the transparent structure at the front of your eye) becomes cloudy, your vision is likely to be severely affected. Severe cataracts can cause blindness if left untreated.

Complications after surgery

It is estimated that less than 2% of people experience any serious complications after having cataract surgery.

Cloudy vision

One possible complication is that the lens capsule (the 'pocket' that the lens sits inside) will thicken and cause cloudy vision. This is not the cataract returning, but is caused by cells growing over the back of the artificial lens.

If this happens, you may need to have another operation to correct it. This will be done with 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 left to continue holding the artificial lens in place.

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

Wearing glasses

The natural lens in your eye can change shape. This is how it enables your eyes to focus on objects that are 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 to wear 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. This is called an accommodating lens.

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

Glossary
Lens
The transparent structure at the front of your eye, just behind your pupil (the black circle in the centre of your eye).
Incision
An incision is a cut made in the body with a surgical instrument during an operation.

Page last reviewed: 13/07/2011

It is not possible to prevent cataracts. However, there are some steps that you can take to reduce the risk of them developing. For example:

  • not smoking 
  • protecting your eyes from sunlight by wearing sunglasses and a hat with a peak or wide brim

Diet

It is well known that a healthy, balanced diet is important for your general health, including the health of your eyes. Eating a healthy diet cannot prevent cataracts, but some experts think that:

  • a poor diet may increase your risk of developing age-related cataracts
  • a healthy diet may slow down the growth of age-related cataracts

As part of your healthy diet, you should eat at least five portions of fruit and vegetables every day.

Eye tests

It is important to have your eyes tested regularly by an optometrist (a specialist who examines eyes and tests sight) even if you do not wear glasses.

You should have your eyes tested at least every two years. This enables cataracts to be picked up early, as well as any other eye conditions, such as age-related macular degeneration (a painless eye condition where you gradually lose the ability to see what is directly in front of you).

Diabetes and cataracts

People with diabetes (a long-term condition caused by too much glucose in the blood) tend to develop cataracts at an earlier age than others. This is because the high levels of glucose in their blood can damage blood vessels, nerves and organs, causing a number of complications.

If you have diabetes, you should follow your GP's healthcare advice carefully. This will help to reduce your risk of developing cataracts, as well as other eye problems, such as diabetic retinopathy (a condition that damages the tiny blood vessels that nourish the retina at the back of the eye).

Glossary
Optometrist
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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