TL;DR
Cataracts occur when the natural lens of your eye becomes cloudy, making it harder to see clearly. This clouding develops gradually, and in many cases, you may not notice it at first.
There are three main types of cataracts, each affecting a different part of the lens and causing distinct symptoms. Understanding these types can help you recognise the early signs and seek timely treatment.
What are cataracts?
Your eye’s lens focuses light onto the retina, which sends visual signals to the brain. In a healthy lens, light passes through clearly. A cataract disrupts this process by scattering or blocking light due to the cloudy areas that form in the lens.
Cataracts can develop in one or both eyes, although they do not spread from one to the other. While age is the most common factor, cataracts can also result from injury, medical conditions, or prolonged use of certain medications.
The three types of cataracts
Although all cataracts cause clouding of the lens, they are categorised by where they develop. The three types are:
Nuclear sclerotic cataracts
Nuclear sclerotic cataracts form in the central part of the lens, known as the nucleus. This is the most common type of age-related cataract. Over time, the proteins in the lens break down and clump together, causing it to harden and turn yellow or brown.
At first, you might notice a gradual decline in your ability to focus on distant objects. Interestingly, some people with early nuclear cataracts find their close-up vision temporarily improves, a phenomenon known as second sight. However, this improvement is short-lived as the cataract continues to develop.
As the lens becomes more opaque, it can distort colours and make it difficult to see in low-light conditions. In advanced stages, night driving can become hazardous due to glare and halos around lights.
Cortical cataracts
Cortical cataracts start in the outer layer of the lens, known as the cortex. They appear as wedge-shaped or spoke-like streaks that point toward the centre of the lens. This pattern can scatter light entering the eye, causing problems with glare and contrast.
You might first notice symptoms when looking at bright lights or during night driving, as the scattered light makes it difficult to see clearly. Over time, these streaks can extend further into the centre of the lens, affecting both near and distance vision.
Cortical cataracts are more common in people with diabetes and may progress more quickly than nuclear cataracts. Because they interfere significantly with light transmission, they can cause a marked reduction in visual clarity even before they are fully developed.
Posterior subcapsular cataracts
Posterior subcapsular cataracts form at the back of the lens, directly in the path of light heading toward the retina. They often develop faster than other types and can cause symptoms to appear within months rather than years.
This type of cataract can make it difficult to read, see in bright light, or recognise faces in sunlight. You might notice a significant increase in glare and halos, along with difficulty adjusting between bright and dim environments.
Posterior subcapsular cataracts are more common in younger people than the other types and are linked to prolonged steroid use, certain eye injuries, or conditions such as retinitis pigmentosa. They can also occur after eye surgery for other conditions.
Recognising the symptoms of cataracts early
While each type of cataract has its distinct characteristics, there are general signs you should watch out for:
- Blurred or cloudy vision
- Increased sensitivity to light and glare
- Fading or yellowing of colours
- Difficulty seeing at night
- Frequent changes in your glasses prescription
If you experience these symptoms, it is important to have a comprehensive eye examination. Early diagnosis allows for better management and planning for any future treatment.
Causes and risk factors
Cataracts develop due to changes in the lens proteins, but certain factors can increase your risk. Age remains the biggest factor, with most cases appearing after 60. Other notable risk factors include:
- Long-term exposure to ultraviolet light without eye protection
- Smoking, which can accelerate lens damage
- Diabetes, which is associated with earlier onset
- Prolonged use of steroid medications
- Previous eye injuries or inflammation
Treatment options for cataracts
The only effective treatment for cataracts is surgery, which involves removing the cloudy lens and replacing it with an artificial one. Cataract surgery is one of the most common and successful procedures, with a high rate of restored vision.
However, surgery is usually recommended only when cataracts significantly interfere with daily life. Before that stage, your optometrist may adjust your glasses prescription, suggest stronger lighting for reading, or recommend anti-glare lenses.
Preventive steps for eye health
While you cannot completely prevent cataracts, you can reduce your risk and slow their progression by adopting healthy habits:
- Have regular eye examinations, especially if you are over 50
- Wear sunglasses with UV protection when outdoors
- Stop smoking to reduce lens damage
- Maintain good control of blood sugar if you have diabetes
- Eat a balanced diet with plenty of fruit and vegetables
It’s important to recognise the three types of cataracts
Understanding the three types of cataracts helps you recognise the different ways they can affect your sight. Whether the changes are gradual or more rapid, being aware of the symptoms means you can take steps early.
Regular eye checks, especially as you get older, are essential for keeping your vision sharp and identifying cataracts before they have a major impact. By knowing the signs and risk factors, you are better equipped to make informed decisions about your eye health and treatment options.
