A cataract is an ocular condition associated with opacity of the lens. It is one of the leading causes of blindness worldwide. Cataracts may be seen at any age but as a consequence of different etiologies.

What Causes Cataracts?

The pathomechanism involved in the development of cataracts involves degeneration or changes to the lens structure, its protein components, or both.  The etiology of cataracts is varied may be classified as:

  • Congenital cataracts may be the result of abnormalities in development, maternal malnutrition, and exposure to infection, drugs, or radiation in utero. Developmental cataracts that present in infancy may be caused by birth trauma, malnutrition, congenital abnormalities, and metabolic disorders.
  • Age-related cataracts are the most common type of cataract. They usually present after the age of 50. Risk factors include age, family history of cataracts, dehydration, smoking, oxidative stress, and poor diet.
  • Traumatic cataracts are often seen in those working in hazardous conditions where there is a risk of penetrating trauma from foreign objects. In rare instances, they may also be caused by electric injuries.
  • Complicated cataracts develop as a consequence of diseases causing chronic inflammation in the eye, including skin diseases, allergies, uveitis, glaucoma, diabetes, and asthma.
  • Metabolic cataracts develop in the setting of diabetes mellitus, galactosemia, galactokinase deficiency, and Lowe’s syndrome.
  • Toxic cataracts are caused by exposure to medications, such as corticosteroids and anticholinesterase inhibitors.
  • Radiation cataracts may be caused by exposure to UV rays from sunlight or artificial radiation, such as infra-red rays and x-rays.

Symptoms of Cataracts

  • Blurry vision
  • Sensitivity to glare
  • Trouble seeing in low light settings
  • Diplopia
  • Changes to color vision
  • Decreased visual acuity

Source: Shiels, A., & Hejtmancik, J. F. (2019). Biology of Inherited Cataracts and Opportunities for Treatment. Annual Review of Vision Science, 5(1), 123–149.