Aniridia can be defined as a rare type of genetic eye disorder that is characterized by the complete or partial absence of the iris. The word ‘aniridia’ is a Greek word which means ‘without iris’ and this condition is also known as Congenital aniridia or Irideremia. The condition usually affects both the eyes and is often also associated with other eye problems like cataract, keratopathy, glaucoma, nystagmus, disorders associated with the macula or the optic nerve and sometimes, even cause retinal detachment. Also Read: Seeing Floating Objects? Get Tested For Retinal Detachment

The iris is the coloured part of the eye responsible for controlling the diameter and size of the pupil and thus regulating the amount of light reaching the retina. The amount of pigmentation of the iris determines the colour of the eyes in every individual. An individual with blue or light brown coloured eyes usually has fewer pigments than people with brown or darker colored eyes. Although this condition varies from person to person, it usually causes impaired vision and extreme discomfort in sunlight. Also Read: Keratoconus - Causes, Symptoms and Treatment
aniridia

Causes

Aniridia is a notable rare disorder that can either occur due to genetic mutation or due to sudden injury. A sudden accident due to a fall, or even a car or work accident may cause partial or even total loss of the iris.  In the case of hereditary or genetic causes, aniridia involves chromosome 11 and a gene, called PAX6, which plays a crucial role in the formation of tissues and organs during the embryonic development of the foetus. These mutations ultimately disrupt the formation of the eyes and the iris within. 

Types

Aniridia can be classified into two types:

Genetic: In this case, aniridia occurs due to the genetic mutation of the PAX6 gene in the parent which ultimately transfers it to the child.

Sporadic: In the case of Sporadic aniridia, the condition happens to a person without any family history of this genetic disorder.

Risk Factors

Aniridia may be associated with certain health conditions including:

  • WAGR syndrome: This syndrome includes Wilm’s tumor, Aniridia, Genitourinary Anomalies and Mental Retardation 
  • Peters anomaly
  • Gillespie syndrome 

 Symptoms

Aniridia varies from person to person. While in some, the absence of a part of the iris is hardly noticeable, whereas in others there is a complete absence of the iris. But the common signs and symptoms affecting both cases include:

  • Photophobia or light sensitivity
  • Glaucoma
  • Nystagmus
  • Retinal problems
  • Corneal problems
  • Cataract
  • Wilm’s tumor
  • Reduction in visual clarity or acuity
  • Aesthetic problems
  • Perforation of the eye 
  • Misshapen pupil
  • Redness of the eye
  • Blepharospasm or tight eyelid muscles
  • Aggravation of bacterial infection
  • Dry eye
  • Blindness

Diagnosis And Treatment

This condition is usually detected right at birth owing to the unusual completely dark pupil of the child without any real iris colour. The doctor also acknowledges the medical history of the patient or in case of a child the genetic history of the parents. In case aniridia occurs at a later stage due to an accident, the doctor usually does a complete eye check-up to look for any damage of the optic nerve, retina, lens, or iris. 

Treatment

The available treatment options usually depend upon the severity and causative factor of this rare eye disorder. To treat this condition, the doctor chiefly tries to diminish underlying symptoms to improve eyesight.

  • Low vision devices to improve poor vision
  • Coloured lenses to improve the appearance of the eye
  • Artificial tears to treat a dry eye problem
  • Medications to lower eye pressure in case of glaucoma
  • Surgical procedure in case of cataract, or corneal problems