Also known as: Congenital Abnormality of the Iris


Aniridia is a rare eye condition present at birth. Usually part or the entire iris (coloured bit of the eye) is absent, giving the appearance of an enlarged pupil. There is an associated underdevelopment of the retina (a light-sensitive film at the back of the eye) leading to reduced vision and nystagmus (involuntary eye movements). Aniridia is caused by a change (mutation) in the PAX6 gene on chromosome 11. The condition is usefully diagnosed by an ophthalmologist (eye specialist) and can be managed with prescription glasses, other low-vision aids and adequate support at school. Complications can include cataractsglaucoma (where the optic nerve is damaged due to changes in eye pressure), corneal scarring (where the transparent front part of the eye becomes damaged) and squint can, but are all treatable. Aniridia is inherited in an autosomal dominant manner. The condition can also develop sporadically (with no family history) due to a deletion on chromosome 11. Some children with sporadic aniridia are at risk of developing Wilm’s tumour of the kidney – this should be screened for and treated appropriately. Affected families should be referred to a genetics centre for information and support.

This overview is intended to be a basic description of the condition. It is not intended to replace specialist medical advice. We advise discussion of your child’s case with a qualified medical professional who will be able to give you more detailed information.


Medical text approved December 2012 by Miss Isabelle Russell-Eggitt, Contact a Family Medical Advisory Panel.

Is there support?

There is no support group for aniridia in the UK. Families can use Contact’s freephone helpline for advice and information.

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