What are cataracts?


A cataract is clouding of the normally clear lens portion of the eye – a gradual process that can eventually impair vision.

The lens of the eye focuses light, so that we can see objects clearly at different distances. It must remain transparent for clear vision. The lens is mostly made up of water and protein, in a precise composition to keep the lens clear and allow light to pass through.

With age, changes in the chemical composition of the lens occur: parts of the protein may clump together and start to cloud a small area of the lens. This is how most cataracts are formed.

Over time, the cataract may grow larger, clouding more of the lens. As the developing cataract blocks or distorts light entering the eye, those affected will experience a gradual, persistent and painless blurring of vision.

Everyone eventually gets cataracts if they live long enough. The lens can start clouding at any age, but cataracts typically start to impede vision after the age of 60.

Cataract is the leading cause of blindness worldwide and responsible for 51% of world blindness, which represents about 20 million people. Cataract is also the leading cause of blindness in South Africa. Here, it’s responsible for about 50% of blindness.

Despite these numbers, the disease is one of the less serious eye disorders, as surgery can restore lost vision in most cases.

Reviewed by ophthalmologist Dr Viresh Dullabh, MBBCh (Wits) FC Ophth SA (CMSA) MMED (UKZN). September 2018.

Read more:

Symptoms of cataracts

Causes of cataracts

Diagnosing cataracts

We live in a world where facts and fiction get blurred
In times of uncertainty you need journalism you can trust. For 14 free days, you can have access to a world of in-depth analyses, investigative journalism, top opinions and a range of features. Journalism strengthens democracy. Invest in the future today. Thereafter you will be billed R75 per month. You can cancel anytime and if you cancel within 14 days you won't be billed. 
Subscribe to News24
Show Comments ()
Editorial feedback and complaints

Contact the public editor with feedback for our journalists, complaints, queries or suggestions about articles on News24.