What is Cataract


What is a Cataract?

A cataract is an opacification, or a clouding of the human (crystalline) lens. In the diagram below, you will see the lens is situated behind the iris and pupil. An image of the real world enters the eye through the pupil and is focused on the retina by lens.

The retina then sends the information of the image to the brain via the optic nerve. When a cataract is present, the lens can no longer focus a clear image on the retina.

Cataract explained

Symptoms of a cataract include:

  • Blurred, fuzzy or hazy vision
  • Frequent changes in spectacle prescriptions
  • Severe decrease in vision when looking at a bright scene or background
  • Glare, halos or tails from headlights when driving at night
  • Feeling that there is a film over the eye(s), or that one is looking through a veil

Although these are common symptoms, not everyone experiences all of them.

Why do cataracts occur?

In people over the age of 60 years, the presence of cataracts is a very frequent finding. It is believed that in this age group, most cataracts are due to the normal ageing process. Cataracts can also occur and require surgery in younger patients.

When is the cataract ready for surgery?

Deciding when to have cataract surgery is best done in consultation with your Eye Care Practitioner (Optometrist) and/or Eye Surgeon (Ophthalmologist). Patients usually choose, and we recommend, cataract removal at a stage where visual impairment interferes with everyday activities, such as driving a car or reading.

Some patients have surgery at an earlier stage. Dr Chau will recommend surgery if he feels that it will result in a significant improvement in vision.

What is the risk of complication?

Cataract surgery is highly advanced microsurgery. In the past it was generally accepted that over 98% of cases were free from complications. We believe that the complication rate will become even less with Femto assisted cataract surgery. There is very little reason for cataracts to be left untreated. However, while cataract surgery is one of the safest forms of surgery; no surgery is completely without risk. Before undergoing surgery, Dr Chau will discuss any potential risks specific to you particular circumstances.

Assessment before surgery

Before proceeding with surgery an initial consultation with the surgeon’s team and the surgeon is required. This appointment will include vision tests and measurements of your eyes. Dr Chau will examine both eyes to assess the overall health of your eyes.

Dr Chau’s clinical assistant(s) will perform a series of measurements, which are used to calculate the power of the intraocular lens (IOL) to be inserted into the eye during surgery.
The intraocular lens replaces the human (crystalline) lens which has clouded, and which is your cataract. The measurements include the shape of the front of the eye (cornea). The corneal curvature is measured by manual keratometry, computerised topography and the Zeiss IOL Master 700. The length of your eye is measured by light Biometry (Zeiss IOL Master 700). Sometimes, ultrasound is also used.


General medical assessment by your family doctor

You should visit your regular family doctor well in advance before the day of surgery. We would like to know that general health is at its best before surgery. Regardless of whether you were originally referred by your family Doctor, Optometrist or by yourself, we will usually inform your family Doctor by letter of all arrangements related to your surgery.

Dr Chau and his Anaesthetist, Dr Glen Bakyew will want to know of all medications that you take a regular basis, well in advance before surgery, in case they affect the operation or the anaesthetic.


The cost of surgery your health insurance cover, and all other costs are fully discussed in detail and in confidence on the same day as your assessment before surgery.