Cataract

A cataract is a cloudiness of the natural lens of the eye which progresses over time and makes it difficult to see. An examination by your optometrist will reveal any changes to the lens of the eye that may lead to cataracts, before any symptoms appear.

What are Cataracts?

The crystalline lens in the eye is a transparent structure that helps focus light on the retina. It is transparent in nature, allowing light to pass through it easily.A cataract is a cloudiness of this natural lens of the eye, which progresses over time and makes it difficult to see. This can be caused by a number of different factors. As the development of cataracts is usually gradual and painless, people often do not notice the slow deterioration in their vision, especially at the early stages. Symptoms can include blurred or hazy vision, halos around lights, double vision, and increased sensitivity to glare. Cataracts mostly occur in older patients, but can be experienced by very young patients, those with trauma, or a history of eye disease or steroid use. Diabetics will get cataracts at a younger age than the general population also.

There are three main types of cataracts that affect patients:

  1. Nuclear Sclerotic Cataracts. This type of cataract is often age related and causes a yellowing of the normally clear lens. It can often cause your prescription to shift in a short-sighted direction, necessitating updates to your spectacles.
  2. Cortical Cataracts. These are whitish, spoke-like cataracts that start at the edge of the lens and radiate centrally over time. They may only cause glare at an early stage, later resulting in blur when they impinge on the central visual axis.
  3. Posterior Sub-Capsular Cataracts. These are cataracts located at the back surface of the lens. Because of their location even a mild cataract can cause a large loss of vision. Often these are the result of previous surgery or eye trauma. They often tend to be the fastest growing cataract.

CAPTION: A nuclear sclerotic cataract showing the characteristic 'brunescence' or yellowing of the lens.

CAPTION: Light shining back through a cortical cataract showing the 'spokes' extending centrally.

CAPTION: A posterior sub-capsular cataract.

About half of all Australians aged between 65 to 74 have some form of cataract, so it is important that people in this age group have their eyes examined regularly.

There is no proven method to preventing cataracts, although cigarette smoking and UV exposure have both been shown to increase your risk of them developing. A broad brimmed hat, and sunglasses that meet Australian standards, should be worn outdoors to reduce this risk.

Cataract extraction surgery is the most common eye surgery performed in Australia, with around 190,000 operations undertaken annually. It is often the treatment of choice once the deterioration in your vision starts to interfere with daily life. Most patients have an artificial lens inserted to replace their own lens, with almost all people having improved vision and quality of life afterwards. Cataract surgery is now a relatively minor procedure that is safe and effective, often performed under local anaesthetic.

Regular eye examinations are key for an early diagnosis and proper management of cataracts. Symptoms can include blurred or hazy vision, halos around lights, double vision and increased sensitivity to glare.