What are Cataracts?

A cataract is a clouding of the lens in your eye,¹ which causes your sight to become cloudy or misty¹ and can eventually lead to blindness.² Cataracts can affect one or both of your eyes.¹

Eye anatomy: How do cataracts affect your eye?

The lens helps to focus the light entering your eye.¹ Here’s how it works:

1. When you look at something, light passes through the cornea, a dome-shaped structure at the front of your eye.^1,3
2. The cornea bends the light to help the eye focus.^1,3
3. The light then passes through the pupil and the lens .^1,3
4. The lens then focuses the light towards the retina at the back of your eye.^1,3
5. The lens is normally clear, which means the light can pass directly through it to focus on your retina, where it gets converted to electrical signals.¹
6. These signals are delivered to the optic nerve and then to your brain.¹ The brain interprets the signals, which is how you’re able to see.¹

DID YOU KNOW?

The lens also allows you to focus on objects at different distances, by changing its shape.¹ This is known as ‘accommodation of vision’.¹

Cataracts usually happen because of changes in a lens – for example, changes in the way the collagen fibres of the lens are arranged and their water content.¹ These changes cause the lens to become cloudy instead of clear.¹ This means light cannot pass directly through the lens, so you will experience problems with your vision.¹

IMPORTANT: A cataract is not a growth or a film growing over your eye.¹ It’s the term used to describe the clear lens of your eye becoming cloudy.¹

How common are cataracts?

Cataracts affect an estimated 95 million people around the world.²  They are among the most common eye conditions in South Africa,⁴ and one of the leading causes of preventable blindness in lower-middle-income countries.²