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What causes cataracts?

man with cataracts reading a newspaper

The main cause of cataracts is advancing age, but it isn’t the only cause. Cataracts usually start developing sometime after age 40, but visual effects can take many years to notice. Cataracts occur when the eye’s lens, directly behind the pupil, slowly clouds up. 

With age, the proteins within the lens can begin to clump together. These clumps are the cataracts, and they can cloud and block vision. No one knows for sure why the eye’s lens changes as people get older. However, researchers have identified several factors that may lead to cataracts or cause them to get worse.

Besides age, cataracts may be caused or worsened by:

  • UV radiation from the sun

  • Diabetes

  • High blood pressure (Hypertension)

  • Obesity

  • Smoking

  • Prolonged use of corticosteroid medications

  • Prolonged use of statin medications

  • Eye injury or inflammation

  • Previous eye surgery

  • Hormone replacement therapy

  • Excessive alcohol consumption

  • High nearsightedness (Myopia)

  • Exposure to toxic substances or radiation

  • Family history of cataracts

Some researchers believe that age-related cataracts are caused by oxidative changes in the eye’s lens. This is backed up by nutrition studies that show fruits and vegetables high in antioxidants — which slow oxidative changes — may help prevent certain cataracts.

SEE RELATED: What is a cataract?

There are different types of cataracts, each with different causes.

In addition to cataracts developing with age, they can also be congenital — present from birth. This can happen when a woman gets severely ill or injured during pregnancy. Congenital cataracts can also be caused by abnormal development.

Sometimes the cause of cataracts is an underlying disease or disorder. These can include one or more of the conditions listed above, such as diseases, injuries, medications and UV radiation.

SEE RELATED: Pediatric cataracts

What probably doesn’t cause cataracts

Stress in psychological or emotional form has not currently been proven to cause or worsen cataracts. But it can affect other parts of the eyes. For example, research suggests stress may increase eye pressure in open-angle glaucoma and may even lead to an attack of angle-closure glaucoma.

There is no evidence that the radiation emitted from computer screens causes or worsens cataracts, according to the American Optometric Association.

Additionally, while dehydration at life-threatening levels can increase the risk of cataracts, a cataract link to mild dehydration has not yet been proven. However, staying properly hydrated will always benefit our bodies — eyes included.

READ NEXT: How cataracts are treated

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