What is a Cataract?

A cataract can be described as a cloudiness or opacity within the lens of the eye.


The lens sits inside the eye, behind the coloured part known as the iris. It is made of crystalline fibres and is responsible for approximately 1/3 of the eye’s focusing ability. When we are born, the lens is very clear and elastic, it is this elasticity that allows children and young people to focus easily.

As we age and approach 40, the lens loses some of its elasticity, this is known as presbyopia, and is the reason adults start to require reading spectacles. It also starts to lose some of its clarity, this happens as the fibres within the lens become more densely packed together. By approximately 65, most human lenses would be described as ‘slightly hazy’ rather than clear.

This is a normal age-related change. As the lens becomes cloudier, an Optometrist or health professional would start to describe this as a cataract forming. They usually develop in both eyes.

As the lens becomes cloudy, some people will start to notice their vision also becomes cloudier. A bit like the difference between looking through a normal kitchen window, and a bathroom window. This cloudiness occurs so slowly and gradually that it doesn’t usually inhibit a person’s lifestyle until the later stages. Whilst a cataract is forming however, you can expect your spectacle prescription to alter, your accuracy of vision to reduce, brightness of colours to seem more faded, and many people experience symptoms of glare.

Glare happens when the light from the environment such as the TV or car headlights, scatters off the cloudy areas within the lens, rather than passing straight through. It is not harmful for the eyes, but can be uncomfortable and an inconvenience. Many people feel unhappy driving at night because of this.

Although cataracts are regarded as natural, there are some risk factors which increase the likelihood of developing them quicker, or at a younger age. These include smoking, UV light and radiation exposure, some medicines e.g. steroids and diabetes.