Aniridia

Aniridia is a condition characterized by the absence or near absence of the iris, the colored, muscular ring in the eye that controls the size of the pupil and regulates the amount of light entering the eye. This absence results in a primarily black appearance of the central eye. Aniridia can be congenital, typically affecting both eyes, or caused by a penetrant injury. Congenital aniridia is not simply an iris defect but a more complex condition affecting multiple parts of the eye, with macular and optic nerve hypoplasia, cataract, and corneal changes. Vision may be severely compromised and the disorder is frequently associated with several other ocular complications, including nystagmus, amblyopia, buphthalmos, and cataract. In some cases, aniridia occurs as part of a broader syndrome, like WAGR syndrome (kidney nephroblastoma, genitourinary anomalies and intellectual disability) or Gillespie syndrome (cerebellar ataxia).