What are Cataracts?

When vision becomes cloudy

9 September 2019
Eye measurement with ZEISS IOLMaster.

A cataract is a medical condition that affects most people sooner or later. It is the most common eye disease and part of the normal aging process. After the age of 50, it is quite probable that the human eye starts to develop some form of this ocular disease. The word cataract is derived from the Latin cataracta, meaning ‘waterfall’ and from the Ancient Greek καταρράκτης (katarrhaktēs), which means ‘down-rushing’. Like water rapidly rushing turns white, it may be a metaphorical term to describe the effect running time has on the whitening of a lens with advanced cataract progression.

  • Impaired

  • Healthy

  • Illustrative visualization of an eye suffering from cataract.

    Vision impaired by cataract

  • Illustrative visualization of an healthy eye.

    Healthy vision

Cataract causes

Cataracts are an eye disorder that occurs typically with increasing age. The natural lens of the eye, called also crystalline lens is mostly made of water and protein. Due to a change in that protein structure over time, the natural lens becomes increasingly cloudy – gradually causing the main symptoms of cataracts.

According to the latest assessment of the World Health Organization (WHO):

  • Cataracts are responsible for 51% of world blindness and remains the leading cause of blindness.
  • This represents about 20 million people.
  • Many people over the age of 50 have some form of this eye disorder.1

At an early stage of cataracts, the crystalline lens starts to become cloudy causing slightly blurred vision. The more the cataract advances, the worse the quality of the image projected onto the retina becomes. Untreated, it may lead to blindness.


Signs to detect a cataract

It starts out slowly with little influence on your sight. The first sign of cataracts may be when you notice that your vision is a little blurry. It may feel like looking through a cloudy piece of glass or a foggy layer on a window. To detect cataracts at an early stage, it is important to know the most common symptoms.

Common symptoms of cataracts include:

  • Gradual deterioration of vision.
  • Hazy or cloudy sight.
  • Faded colour and contrast perception.
  • Increased sensitivity to bright light.
  • Frequent changes of glasses prescription.

You should consider consulting your doctor about the cataract treatment when it starts affecting your vision and quality of life.

Vision Simulation Tool demonstrating visual disorders and IOL options.

Cataract Vision Simulator

What does it look like if your vision is affected by this eye disorder?

The eye's naturally clear lens becomes cloudy. Your eyesight gets blurry, like looking through a frosted window.

This vision simulator demonstrates how eyesight changes when you suffer from cataracts and other visual disorders, such as presbyopia and astigmatism. It also shows how you can improve your vision with surgery. The images simulate the postoperative visual results that can be achieved with different types of intraocular lenses (IOLs), that are used to replace the eye's natural lens clouded by the cataracts. This is the only effective treatment option.

The visual quality provided by the different types of intraocular lenses at different light conditions depends on the characteristics of the IOL. It also depends on many individual patient factors such as: the general health of your eye, the individual healing time and adaptation of the brain to the new conditions.

This visual demonstration is meant to give you a rough idea of what to expect depending on what IOL you chose. Results vary individually from person to person and cannot exactly be predicted after the surgery.

Start vision simulation

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