Cataract Facts

A cataract is a clouding of the eye's natural lens, which lies behind the iris and the pupil. Cataracts are the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world.














Some statistics about cataract surgery in the UK

  • Approximately 330,000 cataract operations are performed each year in England alone.

  • It is estimated that 30% of people 65 years or older have a visually impairing cataract in one or both eyes.

  • 10% of people 65 or over had already had cataract surgery.

  • 95% of cataracts are age-related, usually after age 40.

  • Approximately 40% patients undergo cataract surgery on both eyes.


Cataract Symptoms and Signs

A cataract starts out small and at first has little effect on your vision. As the cataract grows you will notice that your vision becomes more and more blurred. Images appear as if you were looking through a clouded glass.

A cataract may cause glare and make the light from the sun or a lamp seem too bright. You may also notice when you drive at night that the oncoming headlights cause more glare than before. Colours may not appear as bright as they once did.


What Causes Cataracts?

The lens inside the eye works much like a camera lens, focusing light onto the back of the eye in an area called the retina. This allows clear vision. The lens also adjusts the eye's focus so we can see objects close and far away.

The lens is mostly made of water and protein. The protein is arranged in a precise way so that the lens remains transparent. This allows light to pass through the lens without obstruction.

As we age, the protein in the lens starts to clump together and clouds a small area of the lens. This is a "cataract", and over time, it may grow larger and cloud more of the lens, making it harder to see.

No one knows for sure why the eye lens changes as we age, forming cataracts. But researchers worldwide have identified factors that may cause cataracts or are associated with cataract development.


Besides advancing age, cataract risk factors include:

  • Too much exposure to sunlight

  • Diabetes

  • Hypertension

  • Obesity

  • Smoking

  • Prolonged use of corticosteroid medications

  • Statin (Cholesterol) medicines used to reduce cholesterol

  • Previous eye injury or inflammation

  • Previous eye surgery e.g. retinal detachment repair surgery

  • Hormone replacement therapy

  • Significant alcohol consumption

  • High myopia (near sightedness)

  • Family history


One theory of cataract formation that's gaining favour is that many cataracts are caused by oxidative changes in the human lens. This is supported by nutrition studies that show fruits and vegetables high in antioxidants may help prevent certain types of cataracts.