A cataract exists when the natural crystalline lens of the eye becomes cloudy over time, leading to blurring and a gradual loss of vision. It is one of the most common causes of blindness in patients over 40 and can develop in both eyes. It is estimated that over two and half million people in England and Wales suffer from visual impairment as a result of cataracts and the surgery is now the most commonly performed elective procedure in the world, with around 300,000 treatments undertaken every year in the UK alone.


Ageing is the most common cause of cataract development, because as we get older, protein in the lens can clump together and become cloudy. Over time, this clouding grows gradually which leads to cataract formation. Most people over 60 years have mild cataract but surgery is not required if vision remains unaffected. Although in some rare instances, children and young people can develop cataract.

There are a number of factors which may contribute to the development of the condition:

  • Family history
  • Previous eye operation
  • Other eye conditions; injury, inflammation
  • Use of corticosteroid medications
  • Prolonged exposure to ultraviolet radiation e.g sunlight
  • Obesity and a lack of vitamins;
  • Certain medical conditions like diabetes, hypertension and high myopia
Symptoms and signs

The symptoms usually start out very mild with no effect on your vision. However, as the cataract develops, symptoms will become more obvious. These could be light scatter, (e.g. glare from oncoming car headlights) and progressively more short sighted or vision becomes blurry and colours are dulled. The precise symptoms from cataract are largely dependent on the type of cataract, such as;


  • Nuclear cataract- associated with ageing, and forms deep in the nucleus (centre) of the lens.
  • Sub-capsular cataract – associated with diabetes, previous eye operation or steroids
  • A cortical cataract- This is formed in the outer layer of the lens
Cataract Treatment 1

Healthy eye

Cataract clear lens

Clear lens

Eye with cataract

Eye with cataract

Lens clouded by cataract

Lens clouded by cataract

When should I have my Cataract operation?

It is no longer considered necessary or desirable to wait until a cataract has fully developed before undergoing surgery, as it is often easier and less likely to have complication if cataract surgery is performed before it is ‘ripe’. The decision for the operation must be based on patients’ symptoms against the small risk associated with this operation. Surgery is usually encouraged when clouding or other symptoms (such as glare) become noticeable and start to impede the patient’s daily life.

However, waiting for cataract surgery does not harm the health of your eye, and usually good results can be achieved from cataract surgery performed at an early or a later stage.