Cataracts

Published by Bupa's Health Information Team, September 2010.

This factsheet is for people who have cataracts or who would like information about them.

A cataract is a painless clouding of the lens of the eye. Cataracts generally develop over a long period of time, causing eyesight to gradually get worse. They can, if severe, lead to blindness if left untreated.

About cataracts

In the UK, you're more likely to get cataracts as you get older. About a third of people aged over 65 have cataracts in one or both eyes.

Cataracts can usually be treated with surgery, but you only need to have surgery if the cataracts are affecting your vision in such a way that you're unable to pursue or enjoy day-to-day activities such as reading, driving or leisure activities.

The eye

Your eye is ball-shaped and contains fluid.

Near the front of your eye is the lens, which sits behind the iris - the coloured part of your eye. The lens helps you to see things in focus. It directs light rays on to the back of your eyeball (retina), to form an image, which is then sent to your brain.

The lens is normally clear, and it can change its shape to allow you to see things near and far away. When the lens becomes cloudy it's called a cataract.

Types of cataract

There are two main types of cataract.

• Age-related cataracts, which are the most common type.
• Cataracts present at birth (congenital cataracts). These affect between one and six in every 10,000 babies and are usually diagnosed at birth. It's important to get treatment early as congenital cataracts can permanently affect a baby's eyesight. Visual development occurs very early in infancy. If left untreated, cataracts can cause visual impairment even if they are removed later in life.

Cataracts can also be the result of rare diseases or local eye injuries and inflammation (for information, see Causes). This factsheet is about adult cataracts.

Symptoms of cataracts

If you have a cataract, you may have no symptoms. Alternatively, you may have one or more of the symptoms listed below.

• Your vision may get worse, and seem cloudy, fuzzy or filmy - as though you're looking through fog.
• You may have spots in your vision and might mistakenly think your glasses have spots of dirt or scratches on the lenses.
• You may get more glare (dazzling) or see halos from lights or the sun. This can be severe. It may make driving at night difficult because of the glare caused by oncoming vehicle headlights.
• Colours may seem washed out or faded.

Complications of cataracts

If left untreated, cataracts may eventually lead to blindness. In the UK, cataracts are normally diagnosed and treated well before they severely affect your vision.

Causes of cataracts

Cataracts are caused by changes in the structure of the lens of your eye.

As you get older, you're more likely to develop cataracts. Women are more at risk than men. There are other factors that can increase your risk of getting cataracts. These include:

• diabetes
• an injury to the eye
• other eye problems
• exposure to ultraviolet (UV) light from sunlight
• long-term use of steroid medicines
• smoking
• drinking too much alcohol
• a family history of cataracts
• high blood pressure

Diagnosis of cataracts

A GP, an optometrist (a health professional who examines eyes, tests sight and dispenses glasses and contact lenses) or an ophthalmologist (a doctor specialising in eye health) will look into your eyes using a special instrument called an ophthalmoscope.

Eye tests using standard charts will help identify worsening eyesight. It's quite common to be diagnosed with a cataract during a routine eye test without having any symptoms as changes in the lens tend to occur gradually over many years.

Treatment of cataracts

If you have cataracts, you may find that your vision is still good enough when wearing your glasses or contact lenses. But you might consider treatment if your vision has become noticeably worse or can't be corrected with a change in your prescription lenses, and it's interfering with your everyday activities such as work or hobbies.

Left untreated, your lens may become so cloudy that it's impossible to see any detail, although you will always be able to see some light.

Self-help

Wearing glasses may improve your vision to begin with, but your cataracts will probably get worse over time, so this will only be a temporary solution.

There is no known way to prevent cataracts that develop as a result of getting older.

Medicines

So far, no medicine or diet has been found to slow down the growth of cataracts, and there isn't a medicine that can clear a clouded lens.

Surgery

Removing the cloudy lens and putting a new lens in is the only way to improve your vision. The most common operation for this is called phacoemulsification. The cloudy lens is destroyed with sound waves and taken out, and a lens made of a clear artificial material, such as plastic or silicone, is put in. This is usually done under local anaesthesia or with anaesthetic drops. The anaesthetic completely blocks the feeling from the eye area and you will stay awake during the operation.

For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.