Aniridia is a rare genetic eye condition causing incomplete formation of the iris. It is present at birth. Aniridia causes loss of vision in both eyes. People who have aniridia have enormous pupils. The enormous pupil is often called a ‘black iris’. It literally means “without iris.”


Aniridia is inherited from parents. It occurs when the gene responsible for eye development, the PAX6 gene, does not function correctly. The dysfunction of the PAX6 gene causes the eye to stop developing too early.

Side Effects

People who have aniridia may also develop:

  • a tumor in the kidney
  • sensitivity to light
  • nystagmus
  • glaucoma
  • corneal disease
  • cataract
  • lens dislocation
  • optic nerve disease

Treatment options?

Unfortunately, aniridia cannot be treated. However, treatments are available to help prevent the side effects of aniridi.