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Aniridia

Aniridia is a rare condition where the iris (the coloured part of your eye) has not formed properly. It may be missing or underdeveloped.

This page contains a summary of our information on Aniridia. To read our full information, download our factsheet.

What causes aniridia?

Aniridia is a genetic condition, which means it is caused by a change, or fault, in a gene. In most cases, the faulty gene is the PAX6 gene. In a small number of cases it might be another gene.

What are the genetics of aniridia?

Genes usually come in pairs, meaning we have two copies of each gene. You inherit one copy of the gene from each of your parents to make a pair. Your genes give the cells in your body the instructions they need to work correctly. If there is a fault (change) in a gene, it will not work to give the correct instructions to the cells. This means the cells don't develop or work as they should.

How is aniridia inherited?

There are two ways in which aniridia can be inherited from a parent:

  1. A parent can pass on the changed gene when either of them has aniridia. This is called familial aniridia.
  2. A change in the gene can happen randomly when neither parent has the condition. This is called sporadic aniridia.

How can aniridia affect vision?

In aniridia, the eye is unable to control the amount of light entering the eyes because the iris tissue is missing. Their pupils remain large, and their eyes do not adjust to differing lighting levels. As a result, people with aniridia may experience

  • dazzle, particularly in bright conditions
  • difficulty adjusting as light levels change.
  • reduced vision in certain lighting conditions.
  • light sensitivity (photophobia) that can cause discomfort or even headaches for some.

Aniridia nearly always causes other parts of the eye to be underdeveloped. These include the optic nerve and fovea (the very centre of the macula). This can lead to vision problems, including nystagmus (involuntary eye movements).  People with aniridia may also develop other eye conditions, such as glaucoma, cataract and corneal problems. These other eye conditions can affect vision more than the missing or underdeveloped iris itself.

Aniridia and these associated conditions affect everyone differently. So, while some people with aniridia have quite a lot of sight loss, others may have only mild blurred vision.

What other eye conditions can be linked with aniridia?

Other eye conditions can be linked with aniridia, some of which can be present from birth and some which may develop later in life. Not everyone with aniridia will experience all these eye conditions.

The following eye conditions can be linked to aniridia:

Nystagmus

Nystagmus is constant and involuntary movement of the eyes. This uncontrolled movement can affect how clearly a person can see and is likely to reduce their vision. Nystagmus is usually present from birth or very soon after birth.

Foveal or optic nerve hypoplasia

People with aniridia often have foveal or optic nerve hypoplasia. “Hypoplasia” is a term that refers to underdevelopment of tissue and is a condition someone is born with. The degree of “underdevelopment” can vary between different people, so how much it affects someone’s sight can vary.

Cataract

Aniridia may also cause cataracts to develop at an earlier age, often in late childhood, adolescence, or early adulthood. A cataract is a clouding of the lens, and this will cause sight to become cloudy and misty. Cataract may only affect a small part of the lens but if it starts to affect vision a lot, it may require treatment. Cataracts can be safely left untreated for many years if the vision is not badly affected.

Glaucoma

Glaucoma is an eye condition where your optic nerve is damaged by the pressure of fluid inside your eye. Damage to the optic nerve can cause glaucoma in late childhood, adolescence or early adulthood in people with aniridia. Glaucoma treatment can be given to lower eye pressure and prevent damage to the optic nerve, helping to protect sight.

Aniridic keratopathy

Keratopathy simply means an unhealthy cornea. Signs of keratopathy can start anytime from childhood onwards but tend to occur more into adulthood and middle age. Keratopathy usually starts as a ring of clouding around the edge of the cornea, but if it progresses into the centre of the cornea, vision can become hazy or blurry. Keratopathy can make the eye feel dry and uncomfortable, and lubricating eye drops may help with this.

Is there any treatment for aniridia?

Unfortunately, there is no treatment to cure aniridia at the moment.

There are treatments available for some of the eye conditions associated with aniridia, such as cataracts, glaucoma, or keratopathy.

Children and adults with aniridia will usually be monitored by an ophthalmologist (hospital eye doctor) regularly throughout life. This is to ensure that their eye health is monitored for other eye conditions associated with aniridia.

Although glasses and contact lenses cannot improve any sight problems that are caused by aniridia, it’s important for children to have any focusing problems corrected to allow their sight to develop as fully as possible.

People who are light sensitive find that bright light causes discomfort. The level of discomfort can vary from person to person. Although there is no one solution for light sensitivity, many people with aniridia find that shielding their eyes with sun hats, sunglasses or tinted glasses, or sun blinds in cars can help. More information about coping with light sensitivity can be found on our light sensitivity page.

Further help and support

Emotional support and counselling services

It’s completely understandable to be upset when you or your child is diagnosed with aniridia. For a child, it may be difficult to predict to what extent their vision might be affected in the long term. You may find yourself worrying about the future and how you or your child will cope. You may find yourself wondering how aniridia will affect education or employment. You might wonder what future opportunities will be impacted for you or your child.

It can sometimes be helpful to talk about how you are feeling with someone outside of your circle of friends or family. At RNIB, we can help with our Counselling and Wellbeing team. Your GP or social worker may also find a counsellor for you if you feel this might help.

With the right help and support, individuals with aniridia can lead full and positive lives.

The Eye Care Liaison Officer (ECLO)

You may think of further questions about aniridia on your way home from hospital or in the days and weeks following your diagnosis. There is someone to turn to with these questions. Your eye clinic may have a sight loss advisor working alongside the doctors and nursing staff. This advisor may be known as either the Eye Care Liaison Officer (ECLO), the Vision Support Officer or the Early Intervention Support Officer. They are on hand within your hospital to provide you with further practical and emotional support about eye health. To find out if your hospital eye clinic has an ECLO, you can ask at the clinic or call our Helpline.

Alternatively, you can call our Helpline to speak to our advisors within our Eye Health Information Service, as they would be happy to discuss any questions you may have. 

Making the most of your sight

How much aniridia can affect vision can vary from person to person. For a baby or young child, it may be hard to tell what effect aniridia will have on their sight until they’re older and are able to say more accurately how well they can see.

Some people with aniridia may have focusing problems that aren’t caused by the aniridia itself, such as being short-sighted or long-sighted. Their optometrist (optician) may advise that they need to wear glasses. Although glasses and contact lenses cannot improve any sight problems that are caused by aniridia, it’s important for children to have any focusing problems corrected to allow their sight to develop as fully as possible.

You may find some tasks are made easier by making things bigger and bolder. Using contrasting colours can also help to make some things stand out. An example of this could be making the edges of steps stand out using contrasting colours. When you have aniridia, you’ll be more comfortable if your environment causes you minimal glare. This can involve the lighting around you and the devices you’re using as well as using sunglasses or eye shields to control the light entering the eyes.

The low vision assessment

Low vision aids, such as magnifiers can help with reading. Tinted glasses may be useful to control glare. A low vision assessment will look at using these types of aids and explore which ones may help.

A low vision assessment might be appropriate if you are struggling with detailed visual tasks. You can ask your ophthalmologist, optometrist or GP about low vision aids and whether having a low vision assessment is appropriate for you. During this assessment with a low vision specialist, you’ll be able to discuss the use of magnifiers and aids to help you to see things more clearly.

Education

Having the right support at an early age can make a big difference to children with sight loss relating to aniridia. Your local authority (LA) should have at least one qualified teacher of children and young people with vision impairment (QTVI) to work with you and your child both at home and at school. A QTVI is a qualified teacher who can provide support with development, play, and education. At an early stage, ask your local authority to put you in contact with a QTVI They will support you and your child as soon as a visual impairment is suspected or diagnosed.

You can find out more about the practical help we can offer children, young people and families from our website Parenting a child with a vision impairment | RNIB | RNIB or by calling our Helpline on 0303 123 9999.

Employment

If you have sight loss, you may be worried about finding work or staying in your job. Our employment advisors can provide specialist support and advice about employment for people with sight loss. You can contact this team via our Helpline on 0303 123 9999.

Assistive technology

There is also technology available that can help with low vision. Many smart phones and tablets are already equipped with in-built software that can be helpful. This can enable people with low vision to access information. There are also specific apps and low vision devices that may help too. Computer software programmes are available that can also be installed. Our Digital Skills advisors would be happy to chat to you about the assistive technology that is available. You can get in touch with this team by calling our Helpline on 0303 123 9999.

Social services support

Your local social services should also be able to offer local support if you have low vision. They can provide support with staying safe in your home and getting out and about safely.

Registration

You can ask your ophthalmologist whether you or your child are eligible to register as sight impaired (SI, previously referred to as partially sighted) or severely sight impaired (SSI, previously referred to as blind). Eligibility will depend on how much sight has been affected by aniridia. Registration can act as a passport to help from social services and sometimes to financial concessions.  Even if you or your child aren’t registered, a lot of this support is still available to you.

Page last reviewed: Sept. 1, 2022

Next review due: Jan. 31, 2023