Causes of Cataracts

What causes cataracts?

The lens lies behind the iris and the pupil. It works much like a camera lens. It focuses light onto the retina at the back of the eye, where an image is recorded. The lens also adjusts the eye’s focus, letting us see things clearly both up close and far away.

The lens is made of mostly water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it.

But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it harder to see.

Smoking and diabetes contribute to the development of cataract. Or, it may be that the protein in the lens just changes from the wear and tear it takes over the years.

Source: NEI (NIH)1

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Back to: « Cataracts

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What causes cataracts?

The lens lies behind the iris and the pupil. It works much like a camera lens. It focuses light onto the retina at the back of the eye, where an image is recorded. The lens also adjusts the eye’s focus, letting us see things clearly both up close and far away. The lens is made of mostly water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it.

But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it harder to see.

Researchers suspect that there are several causes of cataract, such as smoking and diabetes. Or, it may be that the protein in the lens just changes from the wear and tear it takes over the years.

Source: NEI (NIH)2

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“I don’t usually think of cataract as an eye disease. In most cases, it’s simply a normal aging change of the eye,” says Dr. Rachel Bishop, an ophthalmologist (eye doctor) at NIH. “Typically, cataracts don’t cause damage to the eye the way most eye diseases do.”

Source: NIH News in Health (NIH)3

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Cataracts occur when the normally clear lens of your eye becomes cloudy, restricting the amount of light that reaches your retina, leading to a decrease in vision.

There are many different causes of cataracts.

Source: New Zealand Health4

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What causes age-related cataracts?

Cataracts are when the lens, a small transparent disc inside your eye, develops cloudy patches.

Over time these patches usually become bigger causing blurry, misty vision and eventually blindness.

When we're young, our lenses are usually like clear glass, allowing us to see through them. As we get older, they start to become frosted, like bathroom glass, and begin to limit our vision.

Source: NHS Choices UK5

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What causes age-related cataracts?

It's not entirely clear why we are more likely to develop cataracts as we get older, but some things may increase your risk of cataracts, including:

Source: NHS Choices UK6

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What causes cataracts in children?

There are a number of reasons why a child may be born with cataracts or develop them while they're still young. However, in many cases it isn't possible to determine the exact cause.

Possible causes include:

Read more about the causes of childhood cataracts.

Source: NHS Choices UK7

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Causes of acquired cataracts

Cataracts that develop in children after they're born are known as acquired, infantile or juvenile cataracts.

Causes of this type of cataracts can include:

  • galactosaemia - where the sugar galactose (which mainly comes from lactose, the sugar in milk) can't be broken down by the body 
  • diabetes - a lifelong condition that causes a person's blood sugar level to become too high
  • eye trauma - as a result of an injury to the eye or eye surgery
  • toxocariasis - a rare parasitic infection that can sometimes infect the eyes, spread from animals to humans via their infected faeces

However, most of these problems are either rare or don't usually cause cataracts to develop in children.

Source: NHS Choices UK8

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Marfan syndrome: Other possible eye-related symptoms of Marfan syndrome include:

  • cataracts - where cloudy patches develop in the eye's lens, causing blurred or misty vision

Source: NHS Choices UK9

Causes of Cataracts

Causes of the condition may include:10 Causes of Cataracts:

Causes List for Cataracts

Some of the possible causes of Cataracts or similar disorders may include:11

... Full Causes List for Cataracts »

Genetics of Cataracts

Genes and genetic conditions Cataracts present from birth (congenital cataracts) are sometimes caused by a faulty gene being passed to a child from their parents. This fault means that the lens doesn't develop properly. It's estimated that there's a family history ...12

... More on Genetics »

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References

  1. Source: NEI (NIH): nei.nih.gov/ health/ cataract
  2. Source: NEI (NIH): nei.nih.gov/ health/ cataract/ cataract_facts
  3. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ issue/ aug2013/ feature2
  4. Source: New Zealand Health: health.govt.nz/ your-health/ conditions-and-treatments/ diseases-and-illnesses/ eye-and-vision-problems/ cataracts
  5. Source: NHS Choices UK: nhs.uk/ conditions/ cataracts/ 
  6. ibid.
  7. Source: NHS Choices UK: nhs.uk/ conditions/ childhood-cataracts/ 
  8. Source: NHS Choices UK: nhs.uk/ conditions/ childhood-cataracts/ causes/ 
  9. Source: NHS Choices UK: nhs.uk/ conditions/ marfan-syndrome/ symptoms/ 
  10. Source: Human Phenotype Ontology
  11. Source: Algorithmically Generated List
  12. Source: NHS Choices UK: nhs.uk/ conditions/ childhood-cataracts/ causes/ 

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.