What is a cataract?

A cataract affects the lens of the eye, which is nestled behind the iris. The lens is responsible for generating sharp images on the retina, by using and focusing the light that passes into the eye.

During youth, the lenses in the eye are transparent, flexible and in good shape. As the body begins to age, however, the lenses begin to thicken and the tissues within them break down and clump together. This produces clouding in small areas, which is known as a cataract.

Cataracts keep developing over time and, as they do, more of the lens gets covered with this clouding. A cataract inhibits light and stops the lens from creating a crisp, sharp image on the retina, resulting in blurry vision.

How do I know if I have a cataract?

There are a few signs that will help you identify if you have developed a cataract. Faded or yellow-tinged colours, increased sensitivity to glare and lights and a continual increase in lens prescription are a few symptoms.

If you find yourself needing brighter light when performing activities such as reading or writing, you may be experiencing light distortion as a result of cataracts. Other indications of cataract development include clouded, blurred or dimmed vision and seeing ‘halos’ around sources of light.

Often, the symptoms begin gradually, with only a small part of the eye’s lens being affected. You may not even be aware of the cataract at the beginning. However, as the manifestation grows larger and distorts the light you may begin to have more noticeable indicators.

Are there different types of cataract?

There are four different cataract types, which have slightly different indicators:

1. Posterior subcapsular cataracts
This type of cataract often experiences the fastest progression and affects the eye almost immediately to some degree. Vision impairment may occur with bright light and cause ‘halos’ to appear around lights when in dim surroundings. A posterior subcapsular cataract tends to form directly in the path of light, near the back of the eye’s lens.

2. Nuclear cataracts
Most often associated with aging, nuclear cataracts are normal with the progression of life. At first, this type of cataract will impede distance vision and cause nearsightedness. However, with time, cloudy vision is slowly introduced. This is due to the lens turning yellow, or even brown, which results in clouded vision and difficulty distinguishing between various colour shades.

3. Cortical cataracts
Cortical cataracts are detected on the outer edge of the lens cortex as white or creamy-coloured streaks. As the condition develops, these streaks elongate to the centre of the lens, which impedes the light that passes through the lens’s centre.

4. Congenital cataracts
A congenital cataract is a condition that people are born with, or develop during childhood. Genetics is usually the cause, although these cataracts can also arise through trauma, infection, or conditions such as rubella, myotonic dystrophy, and galactosemia. Unlike other forms of cataracts, congenital cataracts don’t affect vision in every single case.