Cataract is the clouding of clear lens of eye, leading to reduced vision. It is an age-related process.


What is a lens?

Lens is a clear crystalline structure in the eye. It helps in focusing images on retina. Any changes causing denaturation of lens proteins makes it opaque thus blocking visual pathway and leads to blurred vision.


What are the types of cataract?

Depending upon which layer of lens is involved, it is can be –

  • Nuclear – when central nucleus is opacified
  • Cortical – when peripheral cortex involved
  • Subcapsular – when layer beneath capsule of lens is involved


What are the stages of cataract?

  • Immature cataract – here the patient has blurred vision. It affects patients’ daily routine and is an indication for surgery.
  • Mature cataract – here because of total cataract, the patient has no vision and needs urgent cataract surgery.


What are the causes of cataract?

Congenital (since birth)

  • Genetic disorders like Down’s syndrome or galactosemia
  • Infective causes like toxoplasma, cytomegalovirus, herpes

Acquired causes

  • The most common cause is age. Other reasons can be diabetes, trauma, inflammatory prolonged sun exposure, UV rays and drugs like steroids.