Aniridia (Absence of Iris): What It Means, How It's Treated, and What to Expect for Your Child
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
TL;DR
Aniridia is a genetic condition that causes babies to be born without irises — the colored part of the eye. It always affects both eyes, and no matter how much of the iris is missing, it affects vision and often leads to other eye problems such as cataracts, glaucoma, cloudy corneas, and nystagmus. The condition is caused by a genetic change in the PAX6 gene, usually occurring between weeks 12 and 14 of pregnancy. More than 8 in 10 children with aniridia have poor or impaired eyesight, and most develop glaucoma around ages 10–20. Treatment focuses on preserving vision through regular specialist care, glasses or colored contacts, medications, and sometimes surgery — including, in select cases, implanted artificial irises.
Quick Answer
Aniridia is a genetic disorder in which a baby is born without all or part of the iris, and it always affects both eyes.
It is caused by a genetic change in the PAX6 gene that usually happens between weeks 12 and 14 of pregnancy.
If one biological parent has aniridia, there is a 50/50 chance their child will inherit it; about 1 in 3 cases occur sporadically with no family history.
More than 8 in 10 children with aniridia have poor or impaired eyesight, and most develop glaucoma, usually between ages 10 and 20.
What Is Aniridia?
Aniridia is a condition that causes babies to be born without irises — the colored part of your eye. Some babies are missing their entire irises. Others only have part of an iris in each eye.
One defining feature matters for every family: aniridia always affects both of the child's eyes — it is a bilateral condition. No matter how much of the baby's irises are missing, aniridia will affect their vision and can eventually lead to other issues in their eyes later in life.
| Fact | Detail | | --- | --- | | What is missing | All or part of the iris (the colored part of the eye) | | How many eyes are affected | Always both (bilateral) | | When it develops | Genetic change usually between weeks 12–14 of pregnancy | | Cause | Genetic change in the PAX6 gene | | Vision impact | Always affected, regardless of how much iris is missing | | Typical diagnosis | At birth, by visible absence of the iris |
What Does the Iris Do, and What Happens When It's Missing?
The iris is the colored ring of the eye. Its job is to control how much light enters through the pupil, much like an adjustable aperture in a camera. When the iris is missing or incomplete, that light-control system does not work.
Because the pupil can no longer shrink and expand normally, children with aniridia have a hard time adjusting to changes in lighting. Their pupils will look larger than usual, and they might be unevenly shaped. That loss of light control is the direct reason for the light sensitivity and vision problems that follow.
The PAX6 gene is responsible for more than the iris. It helps form the eyes and parts of the brain, spinal cord, and pancreas. This broader role explains why children with sporadic aniridia can face risks beyond the eyes — a point covered below.
What Are the Symptoms of Aniridia?
Because a child is missing their irises, their pupils will look larger than usual. Their pupils might be unevenly shaped, and they will have a hard time adjusting to changes in lighting. These changes lead to a recognizable set of symptoms:
| Symptom | What You Notice | | --- | --- | | Blurry vision | Sight is unclear and unfocused | | Blindness or partial vision loss | Loss of sight in one or both eyes | | Eye pain | Pain in or around the eye | | Light sensitivity (photophobia) | Discomfort or pain in bright light | | Low vision | Permanently reduced visual ability | | Large, uneven pupils | Pupils that look bigger than usual or irregularly shaped |
What Causes Aniridia?
Aniridia is a genetic disorder. It happens when a genetic change affects the PAX6 gene. This gene helps form a baby's eyes and parts of their brain, spinal cord, and pancreas. The genetic change that causes aniridia usually happens between the 12th and 14th week of pregnancy.
| Genetic Fact | Detail | | --- | --- | | Responsible gene | PAX6 | | What PAX6 forms | Eyes, plus parts of the brain, spinal cord, and pancreas | | When the change typically occurs | Weeks 12–14 of pregnancy | | Inheritance risk (one affected parent) | 50/50 chance | | Cases with no family history | Around 1 in 3 occur sporadically |
Having aniridia as a parent does not guarantee that biological children will have it — it just means they are more likely. And aniridia can happen on its own (sporadically) even if neither biological parent has it, in around 1 in 3 cases.
What Are the Complications?
Aniridia's impact rarely stops at the iris. Other parts of the child's eyes might be underdeveloped as well, including their optic nerves and retinas. Children with aniridia are likely to develop other eye issues as they grow up:
| Complication | Description | | --- | --- | | Cataracts | Clouding of the eye's natural lens | | Cloudy corneas | The clear front surface of the eye becomes opaque | | Glaucoma | Most people with aniridia develop this; usually between ages 10–20 | | Nystagmus | Uncontrolled, shaking eye movements |
One complication stands apart from the eyes entirely. Children with sporadic aniridia — the form that occurs with no family history — have a higher risk of developing a Wilms tumor, a rare type of kidney cancer. The genetic change that causes sporadic aniridia is much more likely to impact other parts of the body that the PAX6 gene is responsible for.
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. Because the condition is visible at birth, a formal exam shortly after delivery confirms it.
Prenatal diagnosis is also possible. If you are pregnant and concerned about the fetus's risk of aniridia (or other genetic disorders), talk to your provider about prenatal genetic testing. Your provider will use a blood test to tell how likely it is that the fetus could have a genetic disorder. They might also perform amniocentesis — removing and testing a small amount of your amniotic fluid.
| Diagnostic Step | What It Involves | | --- | --- | | Birth exam | Missing irises are visible; diagnosis confirmed shortly after birth | | Prenatal blood test | Estimates how likely the fetus is to have a genetic disorder | | Amniocentesis | A small amount of amniotic fluid is removed and tested |
What Is the Treatment for Aniridia?
Treating aniridia focuses 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 will be able to prevent symptoms or complications.
Vision Correction and Devices
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 cornea issues, your provider might prescribe medicated eye drops, artificial tears, or other medications. Since glaucoma is the most likely complication, many families will manage this for years.
Surgery
Surgical options address the complications rather than the aniridia itself. Children who develop cataracts may need cataract surgery to remove them. Your child might also need glaucoma surgery. Some children might be able to get implanted artificial irises — this is a relatively new treatment, so not every child is a good candidate for this type of surgery.
| Treatment | Purpose | Notes | | --- | --- | --- | | Regular eye exams | Ongoing monitoring | Throughout life | | Glasses or contact lenses | Improve vision | Standard correction | | Specialized colored contacts | Cover pupils, reduce light sensitivity | Mimic the shape of an iris | | Medicated eye drops and artificial tears | Treat glaucoma or cornea issues | When complications develop | | Cataract surgery | Remove cataracts | When cataracts form | | Glaucoma surgery | Lower eye pressure | When glaucoma develops | | Implanted artificial irises | Restore iris appearance and light control | Relatively new; not every child is a candidate |
When Should I Contact a Provider?
See a healthcare provider as soon as you notice any changes in your child's eyes or vision. Useful questions to ask your provider include how often your child will need eye exams, whether your child is a good candidate for artificial iris surgery, what the chances are that your child experiences complications, and which changes or symptoms you should look out for.
Go to the emergency room if your child has any of the following symptoms:
A sudden loss of vision
Severe eye pain
Seeing new flashes or floaters in their eyes
| Situation | Action | | --- | --- | | Any change in eyes or vision | See a provider as soon as possible | | Sudden loss of vision | Emergency room immediately | | Severe eye pain | Emergency room immediately | | New flashes or floaters | Emergency room immediately |
What Is the Outlook for a Child with Aniridia?
You should expect your child to have vision issues. Your child will need regular eye exams throughout their life to monitor their eye health.
The numbers are sobering but honest. More than 8 in 10 children with aniridia have poor or impaired eyesight. Most people with aniridia develop glaucoma, usually when they are 10 to 20 years old.
| Outlook Factor | What the Data Shows | | --- | --- | | Poor or impaired eyesight | More than 8 in 10 children | | Glaucoma development | Most people with aniridia, usually ages 10–20 | | Monitoring requirement | Regular eye exams throughout life | | Certainty of complications | Not guaranteed — every child's course differs |
But this doesn't mean every baby born with aniridia will definitely face these issues. It can be scary to find out your baby has a condition that will affect their vision from birth. Aniridia can cause lots of issues, but treatments can help. Regular visits with a healthcare provider or eye care specialist will be the key to keeping your child's eyes healthy and protecting their ability to see. The sooner an issue is diagnosed, the better.
Conclusion
Aniridia is a genetic condition present at birth, caused by a PAX6 gene change that typically occurs between weeks 12 and 14 of pregnancy. It always affects both eyes, always affects vision, and often sets the stage for later complications such as cataracts, cloudy corneas, glaucoma, and nystagmus. With more than 8 in 10 children experiencing poor or impaired eyesight and most developing glaucoma in their second decade of life, lifelong specialist care is not optional — it is the single most important factor in protecting your child's remaining vision.
The encouraging part is that the toolkit keeps growing: specialized colored contacts reduce light sensitivity, medications control glaucoma, surgery handles cataracts and pressure, and implanted artificial irises offer a newer option for some children. And sporadic cases need special attention, since they carry a higher Wilms tumor risk that is unrelated to the eyes.
If your child was born with aniridia, schedule regular eye exams with an eye care specialist and ask about artificial iris candidacy. If you notice any sudden change — vision loss, severe pain, or new flashes and floaters — seek emergency care immediately.
Frequently Asked Questions
What is aniridia?
Aniridia is a genetic condition that causes babies to be born without irises — the colored part of the eye. Some babies are missing their entire irises; others have only part of an iris in each eye. It always affects both eyes.
Is aniridia genetic?
Yes. Aniridia is a genetic disorder caused by a genetic change in the PAX6 gene, which helps form the eyes and parts of the brain, spinal cord, and pancreas. The genetic change usually happens between the 12th and 14th week of pregnancy.
Can aniridia be passed from parent to child?
Yes. If one biological parent has aniridia, there is a 50/50 chance their biological child will have it, too. Having aniridia does not guarantee affected children — it makes it more likely. Around 1 in 3 cases occur sporadically with no family history.
What are the symptoms of aniridia?
Symptoms include pupils that look larger than usual or are unevenly shaped, difficulty adjusting to changes in lighting, blurry vision, light sensitivity (photophobia), low vision, eye pain, and blindness or partial vision loss in one or both eyes.
Can aniridia be seen before birth?
Yes. If you are pregnant and concerned about the fetus's risk, prenatal genetic testing is available. A blood test can estimate the likelihood of a genetic disorder, and amniocentesis — removing and testing a small amount of amniotic fluid — can provide more detail.
How common are vision problems with aniridia?
More than 8 in 10 children with aniridia have poor or impaired eyesight, and the condition always affects vision regardless of how much of the iris is missing.
Does aniridia cause glaucoma?
Most people with aniridia develop glaucoma, usually between ages 10 and 20. Children with aniridia are also likely to develop cataracts, cloudy corneas, and nystagmus as they grow up.
What is the Wilms tumor connection?
Children with sporadic aniridia (no family history) have a higher risk of developing a Wilms tumor, a rare type of kidney cancer. The genetic change that causes sporadic aniridia is more likely to impact other body parts the PAX6 gene controls.
How is aniridia treated?
Treatment focuses on maintaining or improving vision: regular eye exams, glasses or contact lenses, specialized colored contacts that mimic the iris to reduce light sensitivity, medicated eye drops and artificial tears for glaucoma or cornea issues, cataract or glaucoma surgery when needed, and — for some children — implanted artificial irises, a relatively new option that is not suitable for every child.
References
Disclaimer: This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
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