Aniridia (Absence of Iris)
What is aniridia?
Aniridia is a condition that causes babies to be born without irises (the colored part of your eye) in their eyes. Some babies born with aniridia are missing their entire irises — others only have part of an iris.
No matter how much of your baby’s irises are missing, aniridia will affect their vision and can eventually lead to other issues in their eyes later in life.
Your provider will probably be able to diagnose your baby with aniridia when they’re born.
Your child will need regular eye exams throughout their life to monitor their health of their eyes.
Aniridia vs. colobomas
Both aniridia and colobomas are genetic disorders that cause babies to be born with missing tissue in their eyes.
A coloboma is an area of missing tissue in your eye. They most commonly affect the iris of the eye, but can develop in other tissue too. Iris colobomas give kids’ eyes a keyhole or cat-eye shaped pupil because of the missing tissue. They usually only affect one eye (they appear unilaterally).
Aniridia affects both eyes (it appears bilaterally) and causes a baby to be born missing part or all of the irises in their eyes.
Your provider will be able to diagnose either aniridia or a coloboma when your baby is born.
Who is affected by aniridia?
Anyone can be born with aniridia.
It’s a genetic disorder, which means it’s passed from biological parents to their children. You might see it referred to as a congenital condition.
If you were born with aniridia, that doesn’t guarantee that your children will have it too. It just means they’re more likely to be born with it than kids whose biological parents don’t have aniridia.
How common is aniridia?
Aniridia affects around one in every 75,000 babies born each year worldwide.
It’s more common in children whose biological parents also have aniridia. Around two-thirds of babies born with aniridia have a parent who also has it.
How does aniridia affect my body?
Aniridia is a bilateral condition, which means it affects both of your child’s eyes at the same time.
Muscles in your iris control your pupil — the small black opening that lets light into your eye. As your iris squeezes or releases your pupil the amount of light reaching the rest of your eye changes. This constant change in size helps you see in different lighting.
Because babies with aniridia are missing their irises, their pupils look much larger and might be unevenly shaped. They’ll have a hard time adjusting to changes in lighting. Your child might have blurry vision and light sensitivity (photophobia).
Other parts of your child’s eyes might be underdeveloped too, including their optic nerves and retinas.
People with aniridia are likely to develop other issues that affect their eyes, including:
Symptoms and Causes
What are the symptoms of aniridia?
In addition to missing irises, symptoms of aniridia include:
- Eye pain.
- Low vision.
- Light sensitivity.
- Blindness or partial vision loss in one or both eyes.
What causes aniridia?
Aniridia is a genetic disorder that affects a baby’s eyes while they’re developing during pregnancy.
Genetic disorders occur when a mutation (a harmful change to a gene) affects your genes or when you have the wrong amount of genetic material. Genes are made of DNA (deoxyribonucleic acid), which contain instructions for cell functioning and the characteristics that make you unique.
The mutation that causes aniridia happens in the PAX6 gene — the gene responsible for forming your baby’s eyes and parts of their brain, spinal cord and pancreas. The mutation that causes aniridia usually occurs between the 12th and 14th week of pregnancy.
Familial aniridia vs. sporadic aniridia
Your provider might refer to the aniridia you child has as either familial or sporadic. Familial aniridia is what your baby will be born with if one of their biological parents passes the PAX6 mutation on to them. If one parent has aniridia, there’s a 50/50 chance their children will too. Familial aniridia makes up around two-thirds of all cases.
Sporadic aniridia happens if your baby is born with aniridia and neither biological parent has aniridia. Sporadic aniridia is caused when something affects the PAX6 in one parent’s sperm, the other’s egg or after conception. This is known as a spontaneous mutation. Sporadic aniridia is around one-third of cases.
Babies born with familial aniridia have a mutated (changed or altered) PAX6 gene. Children with sporadic aniridia usually have a mutation that completely deletes their PAX6 gene, which can cause other issues throughout their body as they grow and develop.
Diagnosis and Tests
How is aniridia diagnosed?
Your provider will diagnose aniridia when your baby is born. You should be able to see the missing irises in your baby’s eyes.
If you’re concerned about your baby’s risk for aniridia (or other genetic disorders), talk to your provider about genetic screening. Your provider will use a sample of your blood to tell how likely it is that your child could have a genetic disorder. They might also perform amniocentesis — removing and testing a small amount of amniotic fluid from the sac surrounding your unborn baby.
Aniridia and Wilms tumors
Children with sporadic aniridia have a higher risk of developing a Wilms tumor — a rare type of kidney cancer. The mutation that causes sporadic aniridia is much more likely to impact other parts of your child’s body that are developed by the PAX6 gene.
Talk to your provider about what to expect and symptoms to look for in your child as they grow and develop.
Management and Treatment
How is aniridia treated?
Treating aniridia is usually focused on maintaining or improving your child’s vision.
Your child will need regular eye exams and visits with an eye care specialist. The sooner your provider diagnoses changes in your child’s eyes, the more likely they’ll be able to prevent symptoms or complications.
Depending on how much of their irises is missing your child might need a few treatments, including:
- Glasses or contact lenses: Just like anyone with vision issues, wearing glasses or contact lenses can improve your child’s vision. Kids with aniridia sometimes wear specialized colored contacts that mimic the shape of an iris to cover their pupils and reduce light sensitivity.
- Medications: If your child develops glaucoma or issues with their cornea, your provider might prescribe medicated eye drops, artificial tears or other medications.
- Surgery: Children who develop cataracts might need them surgically removed.
The Food and Drug Administration (FDA) in 2018 approved a surgery to implant artificial irises to treat aniridia. However, because this treatment is so new, your child might not be a good candidate to receive it. Your eye care specialist or surgeon will tell you which surgical treatments are available and what to expect.
How can I prevent aniridia?
You can’t prevent genetic conditions like aniridia from developing during your pregnancy.
Aniridia — and other genetic conditions — are linked to certain environmental factors (things that happen to or around a pregnant person), including:
- Drinking alcohol.
- Smoking or using tobacco products.
- Using recreational drugs.
Talk to your provider about what you should avoid eating, drinking or doing while you’re pregnant.
Outlook / Prognosis
What should I expect if my child has aniridia?
You should expect your child to have vision issues. More than 80% of kids with aniridia have poor or impaired eyesight. More than half of people with aniridia develop glaucoma, usually when they’re 10 to 20 years old.
This doesn’t mean every baby born with aniridia will for sure face these issues. Talk to your provider or eye care specialist about what to expect as your child gets older.
When should I see my healthcare provider?
See your healthcare provider as soon as you notice any changes in your child’s eyes or vision.
Go to the emergency room if your child has any of the following symptoms:
- A sudden loss of vision.
- Severe eye pain.
- Sees new flashes or floaters in their eyes.
If your child has blindness or vision loss caused by aniridia, your provider will connect you with specialists who can help, including:
- Teachers who work with visually impaired children.
- Low vision therapists.
- Eye care specialists who treat vision loss and blindness.
- Social services and resources to help you improve your child’s quality of life.
These services will help your child learn to maximize their remaining sight and function as independently as possible.
Frequently Asked Questions
What questions should I ask my doctor?
- How will aniridia affect my child’s vision?
- What treatments are available?
- Do they have a higher risk for other issues in their eyes?
- How often should we see our eye care specialist?
A note from Cleveland Clinic
It can be scary to find out your baby has a condition that will probably permanently affect their vision. Regular visits with your provider or eye care specialist will be the key to keeping your child’s eyes healthy and protecting the vision they do have.
Talk to your provider as soon as you notice any changes in your child’s eyes. The sooner an issue is diagnosed, the less likely it is they’ll have severe symptoms or complications.
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