Your lens is near the front of your eye, just behind your iris, which is the coloured part of your eye. It’s normally clear and helps you to see things in focus. Your lens directs light rays on to the back of your eyeball (retina), to form an image, which is then sent to your brain. If your lens becomes cloudy from a cataract, your vision will become blurred.
Cataracts usually occur in adults and are age-related. There are three main types of cataracts and their names relate to the part of your lens that is affected.
- Nuclear cataracts. This type of cataract develops when the centre of your lens (the nucleus) becomes hardened over time.
- Cortical cataracts. This type of cataract begins at the outer edge (cortex) of your lens and spreads towards the centre of your lens.
- Subcapsular cataracts. This type of cataract develops on the back of your lens.
Sometimes cataracts can occur in children. They are named according to the age they develop in children. Congenital cataracts are present at birth or shortly afterwards. Infantile or juvenile cataracts may occur in older babies or children.
Your symptoms will depend on where your cataract is, its size and if you have a cataract in one or both of your eyes. Some of the symptoms of cataracts are listed below.
- Cloudy or blurred vision – this may make it difficult for you to read, watch television or recognise faces.
- You may get more glare from lights or the sun.
- Driving may become difficult, especially at night.
- Frequent changes to the prescription of your glasses or contact lenses.
- Colours may seem washed out or faded.
These symptoms may be caused by problems other than cataracts. If you have any of these symptoms, see your optometrist for advice. An optometrist is a registered health professional who examines eyes, tests sight and dispenses glasses and contact lenses.
If you think you have symptoms of cataracts, it’s a good idea to get your eyes tested by an optometrist. He or she will look into your eyes using a special instrument called an ophthalmoscope.
If you have cataracts, your optometrist will refer you via your GP to an ophthalmologist. An ophthalmologist is a doctor that specialises in eye health.
Eye tests will help identify if your eyesight is becoming worse. You may be diagnosed with a cataract during a routine eye test without having any symptoms. This is because the, changes in your lens occur gradually over many years.
If you have cataracts, your symptoms may be improved by wearing glasses and using brighter lighting. For some cataracts though, bright light can cause more glare. Your cataracts will probably get worse over time, so these things will only be a temporary solution.
If your cataracts interfere with your daily life, you can have surgery to remove them.
To help improve your vision, your cloudy lens can be replaced with a new, artificial lens through a procedure called phacoemulsification. This is a commonly used, safe procedure which takes about 30 to 40 minutes.
Your cloudy lens is destroyed with sound waves and is taken out. It will then be replaced with a lens made of a clear, artificial material, such as plastic.
If you have a cataract in both eyes, the surgery to remove each one will be done at different times. The surgery may be carried out six to 12 weeks apart. See our cataract surgery topic for more information.
Cataracts are caused by changes in the structure of the lens of your eye. These usually happen naturally as you get older. However, there are other factors that may increase your risk of cataracts. These include:
- an injury to your eye
- severe inflammation of your eye (uveitis)
- exposure to ultraviolet (UV) light from sunlight
- long-term use (more than a year) of medicines known as corticosteroids
- drinking too much alcohol
- a family history of cataracts
If left untreated, cataracts may eventually lead to blindness. However, cataracts are normally diagnosed and treated well before they severely affect your vision.
Occasionally cataracts can cause angle-closure glaucoma, particularly if you’re long-sighted. Angle-closure glaucoma happens when the pressure in your eye increases very quickly. It can cause you severe pain in your eye and you may feel sick. If you develop these symptoms, it’s important that you seek medical help immediately to ensure that your sight isn’t damaged permanently.
Can I drive if I have cataracts?
This will depend on how advanced your cataract is and if your sight is within the legal limits for driving.
By law, your vision must meet set standards in order for you to hold a driving licence. These criteria are set by the Driving and Vehicle Licensing Agency (DVLA).
The DVLA standards say that you need to be able to read a vehicle's registration plate in good light from 20m away. It’s fine if you need to wear glasses or contact lenses to do this. If the registration plate dates from before September 2001, you must be able read it from 20.5m away. You shouldn't drive if you can't read from these distances.
If you're concerned whether your vision meets the DVLA standards, book an eyesight test or contact the DVLA. If the vision in your other eye is good, you may still be able to meet the driving standards. However, it can take time to adapt to driving with good vision in only one eye.
Can my cataract come back if I have it removed?
No, a cataract can’t come back after surgery because your natural lens has been removed. However, sometimes, following cataract surgery, you may develop a condition called posterior capsule opacification. This can make your vision cloudy, but it’s not the same as a cataract.
Although a cataract can't come back once it’s been removed, there’s a risk you may develop a complication called posterior capsule opacification.
It's caused by a thickening of the natural lens casing – the part of your eye that holds your lens in place. This lens casing isn't usually removed during surgery but holds the new lens that replaces the cataract. Posterior capsule opacification can develop within a couple of months of your surgery, but it may only come on several years later.
If you develop posterior capsule opacification, you will be offered a minor procedure using a laser to correct your vision. Your vision may be restored to the level it was following your cataract surgery.
It’s important to remember that posterior capsule opacification is not as common as it used to be. It’s thought that less than one in 10 people will need a procedure to treat posterior capsule opacification. This is because of the improvements in cataract surgery techniques and also in the lenses that are used.
How quickly will I lose my sight?
This will vary from person to person.
Your vision will probably keep getting worse if you don't have your cataract removed. This can happen slowly, sometimes over a number of years. You may not realise that you have a cataract if the changes are gradual. At first, you may find that your sight isn’t quite right and over time – it might gradually become cloudier and more washed out.
If you do lose your sight as a result of cataracts, it may be possible to restore it with surgery. However, if your sight loss is caused by something else other than cataracts, surgery may not help to improve it.
- Cataracts. NICE Clinical Knowledge Summaries. cks.nice.org.uk, published September 2010
- Understanding cataracts. The Royal College of Ophthalmologists. www.rcophth.ac.uk, published January 2013
- Facts about cataracts. National Eye Institute. www.nei.nih.gov, published September 2009
- Cataract surgery guidelines. The Royal College of Ophthalmologists. www.rcophth.ac.uk, published 2010
- Cataracts. BMJ Best Practice. www.bestpractice.bmj.com, published 16 August 2013
- Cataracts and cataract surgery. PatientPlus. www.patient.co.uk/patientplus.asp, published 5 November 2012
- At a glance to the standard medical standards of fitness to drive. GOV.UK. www.gov.uk, published 2013
- Cataracts − laser treatment following cataract surgery. Royal National Institute of Blind People. www.rnib.org.uk, accessed 15 April 2014
- Phacomorphic glaucoma clinical presentation. Medscape. www.emedicine.medscape.com, published 1 May 2014
- Angle-closure glaucoma. PatientPlus. www.patient.co.uk/patientplus.asp, published 28 May 2013
- Senile cataract treatment and management. Medscape. www.emedicine.medscape.com, published 24 June 2014
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Reviewed by Kuljeet Battoo, Bupa Health Information Team, September 2014.
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