What is a Cataract?

A cataract is a common condition in which the normally transparent crystalline lens in the eye becomes cloudy. This scatters the light and prevents clear images from reaching the retina at the back of the eye, resulting in reduced vision and glare. Cataracts can develop in one or both eyes.

What are the Symptoms?

Common symptoms include:

  • Blurred Vision
  • Glare and sensitivity to bright light
  • Distorsion or double vision in the affected eye
  • A feeling of looking through a veil or a cloudy window.
  • Trouble driving at night
  • Trouble seeing faces or details clearly.

How does a cataract develop?


As the lens ages, it increases in weight and thickness. As new layers of fibres are formed, the centre of the lens (nucleus) becomes compressed and hardens. This is called nuclear sclerosis. The lens is made of mostly water and protein. The precise arrangement of the protein ensures the lens is transparent to enable light to pass through. Any structural changes in the protein can therefore alter the transparency of the lens, thus affecting the vision.

Modifications of the lens protein also increases pigmentation, resulting in the yellow to brown discolouration of the lens and decreased opacification over time.

Initially, the cataract may be small and the cloudiness will only affect a small part of the lens. 

Age-related cataracts can be classified according to its location:

Nuclear: The cataract is present in the centre of the lens (nucleus). They tend to progress slowly and have a greater impact on distance vision.

Subcapasular: The cataract is present at the back of the lens

Cortical: The cataract forms at the periphery of the lens and moves towards the centre in a spoke-like fashion.


The cataract can also be classified according to its cause:

Age-related: the majority of cataracts are related to structural changes in the protein of the lens with age.

Congenital & Infantile: occasionally cataracts are detected in new born babies, a congenital cataract. If a cataract develops in the first 6 months of life, it is an infantile cataract. In these cases, there may be a genetic factor or they may be associated with other conditions or infections. There may be no known cause.

Traumatic: a cataract may develop following blunt or penetrating trauma that disrupts the lens fibres.

Secondary: A cataract may co-exist with Glaucoma or develop after Glaucoma surgery.

They can also develop as a complication to other conditions, such as diabetes or prolonged use of some medication, such as corticosteroids, may also cause a cataract to develop.

Exposure to UV rays, or radiation may result in the development of a cataract.

Diabetes Mellitus

The eyes lens gets its nutrients from fluid filling the front part of the eye, the aqueous humor. The Aqueous humor provides oxygen and glucose. As blood glucose levels increase, the glucose content in the lens will also increase. The glucose is converted to a substance called sorbitol. Increased amounts of sorbitol cause swelling of the lens fibres and eventually leads to cataract formation.


Surgery is the only way to remove a cataract, however, not all cataracts need to be removed. Depending on the size and location of the cataract and the symptoms you have, a change in your glasses prescription, brighter lighting or anti-glare sunglasses may be sufficient to improve your vision and defer surgery.

Western Sydney eye Doctors has the latest technology required to diagnose your cataract. The Doctor will discuss the treatment options with you once the diagnosis has been made.