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What are cataracts? 

A cataract is a common eye condition that occurs when the lens inside the eye becomes cloudy. The lens is located behind the iris and pupil and helps focus light on the back of the eye (retina). Signals are then sent to the brain which allows us to see. Typically, cataracts develop during our older years, and this is known as age-related cataracts.

How Does a Cataract Affect My Vision?

When we’re young, the lens within our eye is usually clear. The development of a cataract is a gradual and painless process, and so the onset may be hard to spot. Due to the slow clouding of the lens, light is unable to reach the retina, and this results in vision that is slightly blurred or dull. Eventually, the lens may become frosted over, just like a steamy mirror. It’s highly likely that you’ll experience cataracts in both eyes, though in some cases the development will begin in one eye before the other.

How fast do cataracts develop? 

Most types of cataracts progress over several years, without immediately clouding your vision. However, there are also rare forms of cataracts, which develop rapidly and may affect your vision within a few months.  

Types of cataracts 

There are several types of cataracts, some of which are more common than others. It is also possible for more than one type of cataract to affect your eyes at the same time. We’ve explained four distinct variants below: 

Nuclear sclerotic cataracts 

The type of cataracts that optometrists diagnose most frequently is nuclear sclerotic cataracts. This type of cataract forms in the centre of the lens (the nucleus), causing it to harden and turn yellow or brown after some time.  

Nuclear sclerotic cataracts can cause increased short-sightedness, meaning they will cause difficulties when looking into the distance. It may also cause halos and glare around bright lights.  

Posterior subcapsular cataracts 

This type of cataract develops quickly and can impact your vision early on, due to its location in the eye being quite central. It affects the back of the lens, the part that lets light through your eyes, which can then be blocked by the cataract.  

Posterior subcapsular cataracts affect your near vision the most. 

Cortical cataracts 

A cortical cataract is a type where the protein build-up appears triangle-shaped, lining the outer edge of the lens like a crown, the tips of the triangle pointing towards the centre of the lens. They scatter the light that enters the eyes, which causes glare and might affect your vision at night.  

This type of cataract can cause astigmatic shifts in prescription. 

Congenital cataracts 

While most types of cataracts develop later in life, congenital cataracts are present at birth. They could develop if the mother had certain illnesses during pregnancy, such as rubella.  

Congenital cataracts do not typically affect the child’s vision, but in rare cases, they do cover the lens and cause more pronounced vision issues. 

cloudy landscape of mountains at dawn

Causes of cataracts 

The lens of the eyes, which sits behind your iris and is responsible for focusing light that enters your eyes, is predominantly made of proteins and water. With age, the protein in the lens can stick together in a clump and form cataracts. As the cataract progresses, it blocks the light from entering the eye, scattering and dimming it, which results in cloudy or distorted vision.  

In most cases, cataracts are caused by age, as the lens becomes less flexible and transparent with age. However, there are other factors that can expedite the progression of cataracts, or set them off earlier in life, such as medical conditions, traumatic eye injuries, or if you take certain medication to treat other health conditions.  

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Unprotected exposure to the UV rays of the sun can damage the eyes in many ways and it is thought that it is one of the risk factors for cataract development. Those exposed to UV over long periods of time may develop cataracts at an earlier age.  

Though this typically only happens after years of exposure to UV rays, it is always important to protect your eyes properly with UV-protecting sunglasses.  


Certain health conditions can increase the risks of developing cataracts. One example of this is diabetes, as diabetics are more likely to develop a cataract earlier in life after increased blood sugar levels affect the protein build-up, and the lens of the eye becomes cloudy more quickly.  

Other diseases that are linked to the progression of cataracts include rubella, down syndrome and uveitis. 


Long-term use of steroids typically used to treat arthritis, asthma or multiple sclerosis, can cause cataracts to occur earlier in life. You should always inform your optometrist when you are using such medication to treat other conditions, so they can look out for signs and offer appropriate advice and management.  


Cataracts can be caused by ocular trauma, after an injury to the head or eyes, from past eye surgery or radiation. Trauma can either disrupt the structure of the lens immediately, leading to a rapid progression of cataracts, or set off the development of a cataract that takes several years to progress.  

Symptoms of cataracts 

Most forms of cataracts progress for several years, before changes in your vision become apparent. However, once the cataract does affect your vision, its symptoms include blurred and cloudy vision, glare when looking at lights in dark environments and colours that look faded. 

Cloudy vision 

As the protein in your lens starts clumping up, your vision can become fuzzy or blurry, increasing gradually to dull your vision. Cloudy vision typically affects the vision in either one or both eyes of those with posterior subcapsular cataracts or nuclear cataracts.  

Trouble seeing at night 

As nuclear sclerotic cataracts start to develop, the lens of your eyes may turn yellow or brown. This affects your ability to see clearly when it is dark and may impact activities such as driving at night. Further, you might either start seeing halos around lights or feel sensitive to bright lights at night, which can also lead to complications while driving in the dark.  

Reduced colour perception 

Due to the possible discolouration of your lens, and protein build-up causing it to turn yellow or brown, the light that enters your eyes may have a yellow tint. Depending on the severity of cataracts, this may change the way you see colours, especially shades of blue or purple.  

However, in the case where colour is affected, your previous colour perception will likely be restored after the cataract is surgically removed.  

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How Are Cataracts Diagnosed?

Cataracts can be detected during a simple routine eye test. As Opticians look through your lens, they will be able to spot anything that is out of the ordinary. They’ll be able to determine how progressed the condition is and provide advice on management and treatment going forward. In some cases, your Optician may refer you for further tests with an Ophthalmologist.

Treatment options for cataracts 

Most people choose surgery for the treatment of cataracts, but if your optometrist detected the cataract during its early stages, the symptoms and effects can be managed with stronger prescription glasses or sunglasses. However, if the cataract is significantly affecting your vision and your lifestyle, surgery will be the only treatment option. 


Cataract surgery is a routine procedure for most ophthalmologists in the UK, which only takes one hour.  

You will be awake during the surgery, but while you may notice lights and movements, the surgery is typically completely painless, as your surgeon applies numbing eye drops prior to the surgery. 

There are various types of surgeries to remove cataracts, but for all of them, the ophthalmologist makes an incision to break up the lens and remove the cataract. After this, the lens is replaced with an artificial lens.  

At what stage can cataracts be removed? 

In the UK, you can get your cataracts removed as soon as you notice it affecting your vision significantly, to the point where it impacts your everyday life such as driving. 

After cataract surgery 

Usually, your vision improves a few days after the surgery. Although most people recover without any issues, it is possible for the intraocular lens to cloud over. This can happen within a few years after the surgery, or a decade later.  

In this instance, you will likely undergo a YAG laser treatment. This procedure is not invasive like the initial cataract surgery and only takes up to twenty minutes. The ophthalmologist will use a laser to make a small hole in your lens membrane. This will allow light to pass through again, resulting in clear vision. 

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