The most common cause of cataracts is aging. Over time, proteins in the lens of the eye form clumps that reduce the amount of light received by the retina. Additionally, the clear lens can slowly take on a yellow or brown discoloration with age. This changes the appearance of certain colors, such as blues and purples.

Older adults with a history of systemic health conditions, such as diabetes, allergies and pneumonia, are at an increased risk of cataracts.

Other potential causes of cataracts include:

• Exposure to ultraviolet light, x-rays or other radiation and infrared heat
  
  
• Eye surgery or procedures including vitrectomy
  
  
• Eye injury
  
  
• Congenital eye defects
  
  
• Diabetes or elevated glycosylated hemoglobin (blood hemoglobin that attaches to glucose)
  
  
• Some medications, such as corticosteroids and some other immunosuppressives

There are also several factors that can increase the risk of developing cataracts. These include:

• Smoking
  
  
• Uveitis (an inflammation of the uvea, or colored parts of the eye)
  
  
• Alcohol abuse
  
  
• High blood pressure
  
  
• Nutritional deficiencies
  
  
• Proteinuria (abnormal amounts of protein in the urine)
  
  
• Exposure to lead