Introduction to cataracts

Cataract refers to cloudy changes in the lens of the eye, which sits just behind your pupil, the black opening in the centre of your coloured iris.

In the healthy eye, light enters through the cornea (the transparent window at the front of the eye), then passes through the pupil and the lens. The lens helps focus light rays on the light-sensitive cells within the retina at the back of your eye.

When a cataract forms, the normally clear lens develops semi-opaque or fully opaque areas causing it to become cloudy and less transparent. Lens opacities range from minimal to advanced and, in the worst cases, create an entirely white lens. Over months or years, cataracts become worse and start to affect vision. Eventually, eye surgery will be required to remove and replace the lens. Glasses and contact lenses will not correct the vision problem; only cataract surgery with the implantation of a new intraocular lens will correct your cataract symptoms and improve your sight.

Cataracts are most commonly a result of the ageing process and become increasingly prevalent after the age of 60 when the onset of vision problems begin. The time for surgery is when cataracts have advanced sufficiently to impair your eyesight and negatively affect your daily life, a consultation with a specialist eye doctor will help determine if cataract surgery is right for you after assessing your eye health.

A ‘waterfall’

A mature or advanced cataract can have a white appearance.

The word cataract comes from the Latin cataracta meaning ‘waterfall or floodgate’ and refers to the white appearance of the pupil in advanced cataracts.

It is rare to see such advanced ‘mature’ cataracts in the developed world, but they are not uncommon in developing countries where conditions make it harder to prevent cataracts worsening.

However, less advanced cataracts are very common in all countries. Half of all people will have cataracts by age 80, rising to 70% by 85, according to the North London Eye Study.

Cataracts and ageing

Poor vision is not an inevitable part of getting older. Cataracts are the most common cause of reversible vision loss in the UK. Cataract surgery is a simple procedure to regain vision; hence surgery is usually a walk-in, walk-out day-case procedure using only a local anaesthetic.

Ageing is by far the most frequent cause of the development of cataracts. Basically, if you live long enough, then you will get cataracts, and it can be considered a completely normal part of getting older.

Half of all people will have cataracts by age 80, rising to 70% by 85, according to the North London Eye Study.

Fortunately, a specialist eye doctor can remove a cataract with a relatively quick day-case procedure, without the need for a general anaesthetic. For instance, in the UK, 98% of all cataract procedures are carried out without the need to stay overnight in a hospital.

There has been a revolution in the modern lens design to correct the need for reading glasses and so patients have a more comprehensive selection than ever before with the new intraocular lens designs.

Cataracts are most commonly as a result of ageing and become increasingly prevalent after the age of 60.

Cataracts video animation

The following cataracts video courtesy of the US National Eye Institute describes the anatomy of your eye and how a cataract develops, plus the effect it has on your vision.

Article Authors
Publisher: London Cataract Centre
David Allamby surgeon
David Allamby MD
Minita Shah optometrist
Minita Shah

How common are cataracts?

Half of all people will have cataracts by age 80. The North London Eye Study found that the prevalence of cataract increases with age. Visually impairing cataracts were present in 71% of people aged 85 or older.

In the UK, Age-related cataracts develop in around 20% of those aged 70. This rises quickly to 50% by 80 years old and just over 70% of those aged 85 or older. Cataracts are the most common cause of reversible vision loss in the UK.

The % of people who have cataracts based on age are:

  • 16% of people aged 65 to 69 years
  • 24% of people aged 70 to 74 years
  • 42% of people aged 75 to 79 years
  • 59% of people aged 80 to 84 years
  • 71% of people aged 85+

Who gets cataracts?

The most common cause of cataracts is ageing. Cataracts are also a little more common in women. There is also some variation according to ethnicity, with a lower age of incidence in Indian and Bangladeshi patients.

Even though cataracts typically affect those age 60 and above, they can also affect young children and even babies (childhood and congenital cataracts).

  • The elderly
  • Young children and even babies
  • Caucasians more frequently
  • More common in diabetes
  • Smokers
  • Greater time out in sunlight

Worldwide, cataracts are the leading cause of preventable blindness. Cataracts are responsible for 51% of all world blindness (20 million people) and as such, are an international priority for the World Health Organization (WHO).

While lots of cataract surgery patients are in their 70s, more and more people in their 40s are getting the eye surgery. In fact, surgeons estimate that 1-2 percent of operations are on patients in their 40s.

Incidence varies with race: 70% of US Caucasians have cataracts by the age of 80. Compare that to 61% of Hispanic Americans and 53% of African Americans.

Half of all people will have cataracts by age 80, rising to 70% by 85

Types of cataracts

There are multiple different types of cataracts, depending on the location of the opacity within the natural lens
Some are very slow to develop, gradually reducing vision over a number of years, whereas others can progress more quickly, even within weeks or months.
Types of cataract

Subcapsular cataract

Posterior subcapsular cataracts appear at the back of the lens and often produce initial problematic symptoms of glare from bright lights, e.g. car headlights, before progressing on to general vision reduction. People with diabetes or those taking high doses of steroid medications have  a greater risk of developing a subcapsular cataract.

Nuclear cataract

Are most commonly associated with ageing. These central lens changes start as a yellowing deep in the central nucleus of the lens, later becoming brown (known as lens brunescence). They cause a general reduction in visual clarity and add a yellow hue to colours.

Cortical cataract

White, spoke-like opacities found in the lens cortex, the outer part that surrounds the nucleus. Cortical cataracts begin in the periphery and then progress inwards to the centre.

Symptoms of cataracts

Bright light, for example from the sun or car headlights, may produce glare or a whiteout when shining from a particular direction.
Faded colours
Colours can appear less bright or faded, producing a washed-out appearance
Blurred vision
Vision becomes blurred or hazy, as though looking through a frosted piece of glass, affecting all or just patches of the visual field.
Glasses unhelpful
The blurriness is not corrected by wearing glasses.
An increase in short-sightedness (myopia) causing a temporary improvement in near vision. Reading vision may improve.
Yellow hue
Vision may take on a yellow hue, although the change is slow and may not be noticed. Vision may also become doubled

Cataracts can develop over months or more commonly years and, initially at least, may present no symptoms

Cataracts usually affect only a small part of the lens in the early stages but will progress and extend over time. Cataracts may develop in one eye at first, but very typically go on to affect both eyes.

Cataracts are not painful or itchy. The eyes are not red or inflamed, and will usually appear normal. In very advanced cataracts, the pupil may become grey or white (the white appearance was likened to a waterfall, from where cataracts get their name).

The location of the cataract will determine the kinds of symptoms you will experience:

Nuclear cataract often leads to an improvement in near vision because of an increase in short-sightedness. The patient may feel their eyesight is actually getting better, though, as the cataract progresses, vision will become worse.

Cortical cataract may not produce any symptoms until it extends centrally and reaches the visual axis within the pupil. At this point, vision will quickly deteriorate.

Subcapsular cataract may produce little in the way of symptoms until it becomes quite advanced, although there may be early effects of glare from bright lights.


Click here to book a cataract surgery consultation with our friendly team. We can advise you on the right procedure.

What causes cataracts?

The most common reason for developing cataracts is ageing, though there are many other factors which have been linked to their development. Some of the known causes or risk factors for developing cataracts are listed below.


The components of the natural lens are mainly proteins and water, arranged as regular clear fibres in concentric layers, rather like an onion. The arrangement of these fibres and proteins is very precise, resulting in transparency that lets light pass through the lens and also focused to form an image on the retina.

The primary cause of cataracts, while not fully understood, appears to be clumping together of proteins, with unequal distribution of protein and water within the lens. This clumping can lead to a small area of opacification which can extend over time as the patient ages. As this clouding increases and affects the line of sight in the central lens, vision is affected.


Cataract prevention

There is controversy about whether cataracts can be prevented, as no studies to date have demonstrated how to avoid or slow their progression.

Although research studies have not shown that antioxidants supplements in pill form can help in preventing cataracts, a large study recently showed that a diet rich in vitamins and minerals was associated with a reduced risk of developing cataracts. There may be several approaches that might be of help in reducing your risk of cataracts:

  • Regular eye examinations can help detect cataracts and other issues before they become a problem.
  • If you are 45+, you should have an eye test every two years, or yearly if you are at increased risk, e.g. a close family member having glaucoma.
  • Reduce alcohol use, as we know that excessive consumption can increase the risk of cataracts.
  • Wear sunglasses that block 100% of ultraviolet (UV) rays when you’re outdoors, as UV radiation from the sun may contribute to the development of cataracts.
  • Carefully control other health issues, especially if you have diabetes or other medical conditions that can increase your risk of cataracts. Keep to a healthy weight.
  • A healthy diet that includes fruits and vegetables could potentially reduce your risk of cataracts. Fruits and vegetables contain antioxidants, which may help maintain the health of your eyes.
  • Stop smoking, as it increases the likelihood of developing cataracts, as well as a wide range of other health issues.


Treatment for cataracts

The definitive treatment of cataracts is surgical removal. This is combined with the implantation of intraocular lenses, or IOL for short.

You can learn all about treatment here in our comprehensive guide to cataract surgery.


Is treatment available for cataracts?

Yes, cataract treatment is available. The only solution is to have your cataracts removed surgically, usually with a day-case procedure. There is no need for general anaesthesia as numbing eye drops suffice in most cases. You can learn more with our complete guide to cataract surgery.

Does my insurance cover cataract surgery?

Your health insurance plan may cover cataract surgery. You will need to confirm with your insurer on the specifics of your policy. If you wish to upgrade to a premium multifocal lens implant, expect to pay to cover this additional cost.

It is always a good idea to have a conversation with your selected clinic as they likely have a great deal of experience in dealing with health insurance companies for the private cover of cataract surgery treatments. They may be able to liaise on your behalf and arrange payment.

How much does cataract surgery cost?

Cataract surgery is typically around £3000-4000 per eye, depending on the centre, the technology used and artificial lens implant selected. Cataract surgery may be covered by your health insurance plan. You can click here to learn more about cataract surgery prices at London Cataract Centre.

Lesya Zvarun

Clinic Manager

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