What Causes Cataracts?

The lens inside the eye works much like a camera lens, focusing light onto the retina for clear vision. It also adjusts the eye's focus, letting us see things clearly both up close and far away.

The lens is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and let 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, 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's 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:

  1. Ultraviolet radiation
  2. Diabetes Mellitus
  3. Hypertension
  4. Obesity
  5. Smoking
  6. Significant alcohol consumption
  7. Drugs (prolonged use of corticosteroid, chlorpromazine and other phenothiazine-related medications)
  8. Statin medicines used to reduce cholesterol
  9. Nutritional deficiency
  10. Previous eye injury or inflammation
  11. Previous eye surgery
  12. Hormone replacement therapy
  13. High myopia
  14. Family history

One theory of cataract formation is that many cataracts are caused by oxidative changes in the human lens or nutritional deficiency. Although the results are inconclusive, studies suggest an association between cataract formation and low levels of antioxidants (for example, vitamin C, vitamin E and carotenoids). Further studies may show that antioxidants can help decrease cataract development.