Cataract is the term given to the misting or hazing of the lens in your eye. Cataracts lead to poor vision and blindness, but in most cases can be easily remedied by a fairly minor operation.

When you develop cataracts your vision slowly becomes more misty. You may see haloes around lights and may find vision worse in bright sunlight. You may be dazzled more easily by bright lights. Your colour vision may not be as good as it was.

It is not possible to correct the problems caused by cataracts by just getting new spectacles. In fact, the first you know about it may well be when the optician tells you that you have cataracts when you go for a routine eye test.

The majority of cataracts are caused by ageing of the eye. It is said that some degree of cataract will happen to all of us if we live long enough. Typically, though, this may be noticed from 50-60 years and onwards.

Certain other conditions of the eye that cause inflammation (for example uveitis) and eye injury might lead to cataracts occurring earlier in life. Other conditions affecting your system as a whole, for example diabetes, are linked with a higher risk of developing cataracts. Certain drugs, including steroids, may make you more likely to develop cataracts early.

Excessive exposure to sun and to radiation increase the risks of developing cataracts. Smoking and alcohol have both been implicated.

Some rare conditions lead to babies being born with cataracts (congenital cataracts). If this occurs it is very important that it is detected early so that the cloudy lens can be removed, as the development of normal vision relies on the eye being able to see in the early months and years.

This is usually by your doctor or optometrist, although other professionals my well point it out to you. They will usually use a hand-held torch with a lens (ophthalmoscope), or a rather more elaborate apparatus called a slit-lamp, to examine your eyes. The lens, which starts off clear, may have areas that are cloudy (lenticular opacities) or may be generally milky in appearance. Sometimes the cataract makes it difficult to see the back of the eye properly.

Your doctor will arrange for you to see a specialist (ophthalmologist).

The only effective treatment for cataracts is to remove the cloudy lens. This is not done with a laser, but by a tiny probe that goes into the eye and dissolves the lens using very fast sound waves (ultrasound). This process is known as phacoemulsification. Usually a tiny plastic lens is put in to the place where the natural lens was, in the same procedure. This is known as intraocular lens implantation. The whole process is very quick, often taking only 15-20 minutes.

Most times this operation is done while you are awake, with local anaesthetic. Even the most nervous of people seem to find this very easy to go through.

No treatment, however minor, is without any risks, but the risks of serious complications are small and the success rate high. Your specialist will discuss possible complications before you undergo the operation. The most common complication, which occurs in up to one person in five within two years of the operation, is for the back layer of the clear pocket in which the lens lies (the capsule) to become cloudy. This is dealt with by laser treatment that removes this cloudy layer (YAG Laser capsulotomy).

You will have eye drops given to you for use after the operation. These contain a steroid to reduce inflammation and an antibiotic to prevent infection getting in to the eye.

You can not stop yourself getting cataracts by any specific changes to your lifestyle, but it does make sense to try to reduce the risk factors. Probably the most important of these that are known are:

• If you smoke, stop smoking
• Avoid bright sunlight, wear broad brimmed / peaked headwear, and use sunglasses that cut out UVA and UVB

• Understanding Cataracts (PDF) (The Royal College of Ophthalmologists of London)
• How to avoid Cataracts (University of Maryland)
• Evidence based medical information (Bandolier, May 1996)