The term cataract is used to describe a clouding within the natural lens of the eye. When light enters the eye, it passes through the cornea (the clear window on the surface of the eye), and then through the pupil. Behind the pupil is the lens of the eye. The lens focuses light rays onto the retina (the light sensitive film) at the back of the eye. The retina sends this signal from the eye to the brain. The eye functions can be compared to a camera with a system of lenses (cornea and lens), aperture (pupil) and film (retina).

With the development of a cataract, the lens becomes cloudy.  The light is distorted and is not focused clearly on the retina.  Vision is reduced and blindness can eventually result.  Almost everyone who lives a long life will develop cataracts.  Most cataracts mature slowly over several years however some cataracts may develop rapidly within a few months.


The most common cause of cataracts is ageing. Age-related cataracts develop as a result of exposure to ultraviolet light as well as natural changes within the lens.

Some cataracts may also result from the use of certain medications such as steroids (cortisone) or some diseases such as diabetes.  Smoking may speed up the progression of certain types of cataract.  Occasionally an injury or blow to the eye may cause a traumatic cataract.  Sometimes cataracts run in families and a small number of babies are born with congenital cataracts.

Fortunately, most cataracts can be successfully removed and vision restored with modern microsurgery techniques.


Cataracts, and their symptoms, vary from person to person. Some common symptoms of cataracts are:

  • Blurred vision
  • A gradual loss of colour vision – objects appear duller
  • Difficulty reading
  • An increasing need for more light to see clearly
  • Glare
  • A tendency to become more near-sighted because of the increasing density of the lens
  • Frequent changes of prescription glasses
  • An increased sensitivity to sunlight or car headlights
  • Double vision, even if only one eye is open

Most people who develop cataracts experience only some of these symptoms.  It is important to realise that these symptoms do not necessarily indicate the presence of a cataract.  A person experiencing these problems should have a complete eye examination to ensure a cataract is present.

In the past, people with cataracts were told to wait until their cataracts ‘ripened’ or ‘matured’.  This meant living through years of slowly deteriorating vision.  With advances in modern microsurgical techniques, cataract surgery has far fewer complications and more rapid visual recovery than in the past.  A cataract is now generally removed when deteriorating vision interferes with a person’s quality of life and they want to see more clearly.

Please consider all of your options before having cataract surgery.  To get you started visit the Cataract Surgery Options page.