Aniridia is a condition in which the iris tissue (the colored part surrounding the pupil) is completely or partially absent, either congenital or very rarely developing later. Its Latin meaning is “absence of the iris”. It usually affects both eyes and can significantly reduce vision.
Main Features of Aniridia:
- Vision loss: Sensitivity to light (photophobia) and low visual acuity are common.
- Nystagmus (involuntary eye movements)
- Glaucoma (increased intraocular pressure – may develop with a probability of up to 50%)
- Cataract (may develop even at an early age)
- Foveal hypoplasia (failure to develop the central part of the retina)
- Corneal problems (panniculation or corneal opacification)
Causes:
Aniridia is usually a genetic disease. The most common cause is:
- Mutations in the PAX6 gene. This gene plays a critical role in the development of the eye.
- It can be inherited with autosomal dominant inheritance; that is, if the mother or father has it, the child has a 50% probability of having it.
- Sporadic (newly formed) mutations can also be seen.
Aniridia is Also Associated with Some Syndromes:
WAGR syndrome:
- W: Wilms tumor (kidney cancer)
- A: Aniridia
- G: Genitourinary anomalies
- R: Mental retardation
Therefore, children with aniridia should be closely monitored for Wilms tumor.
Treatment / Management:
There is no complete treatment, but supportive treatments are applied:
- Artificial iris
- Sunglasses, contact lenses (colored or light filtered)
- Glaucoma treatment
- Cataract surgery
- Vision rehabilitation
- Genetic counseling