Congenital cataracts

A cataract can make your vision blurry, a bit like trying to look through frosted glass. Some babies are born with cataracts or develop cataracts at a very early age. This is known as congenital or infantile cataracts.

The lens of your eye is usually clear, but a lens that is misty or cloudy is said to have a cataract. Cataracts can cause your sight to be blurry or hazy, a bit like trying to look through frosted glass. It is not a layer of skin that grows over your eye or eyes.

Some babies are born with cataracts and some develop them in the first six months of their lives. When a baby is born with a cataract it is called a congenital cataract. If a cataract develops in the first six months of life it is known as an infantile cataract.

Children can have cataract in one (unilateral) or both (bilateral) their eyes. Most children with cataract in only one eye usually have good vision in the other.

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Quick links
– How the eye works
– Types of congenital or infantile cataract
– Causes of congenital cataracts
– Cataract and visual system development
– Diagnosis
– Treatment
– After cataract surgery
– Conclusion

How the eye works

At the front of your eye is a clear tissue called the cornea, it allows light to enter the eye. Your cornea focuses light through your pupil which is a hole in the centre of your iris, the coloured part of your eye. Behind the iris is your lens, this also focuses the light coming through the cornea. Both the cornea and the lens focus the light coming into your eye onto an area of your retina.

Your retina is at the back of your eye and lines the inside of your eye ball. The retina is made up of a number of layers but the most important for vision is the layer made up of cells called photoreceptors. Photoreceptors are cells which are sensitive to light. When light is focused onto the retina the photoreceptors react and convert the light into electrical signals.

When light enters your eye it is focused first by the cornea and then more accurately by the lens so that it reaches the retina properly. The focusing that the cornea and lens do help to make your vision clear and sharp. When the light reaches the retina the photoreceptors react to the light reaching them by sending a small electrical charge through the optic nerve to the brain. The photoreceptors react differently to different light levels or lighting conditions and this changes the nature of the electrical signals that are sent through the optic nerve. When the parts of your brain that deal with vision receive these electrical signals, they make sense of them and this provides you with the pictures that we call sight. All this happens so quickly it is almost instant.

Types of congenital or infantile cataract

There are many types of cataract. Some affect vision and others never do. A cataract located towards the centre of the lens is more likely to affect vision and visual system development, than one which is around the edge of the lens, though this will depend on its size and how dense the cataract is.

Very dense cataracts can cause blindness in babies if left untreated. The ophthalmologist (eye doctor) will check your child's eyes and vision and be able to tell you how much the cataract is affecting your child's vision.

Congenital cataracts can continue to develop, although this normally takes months to years. The ophthalmologist would assess how much the cataract is affecting your child's vision and then discuss treatment with you if they feel it is needed.

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Causes of congenital cataracts

Around three to four per 10,000 children born in the UK have a cataract which affects vision. About a third of cataracts do not have any cause and are not linked with any other disease or condition.

A unilateral cataract (in one eye only) usually has no known cause and it is something that can just happen for no reason. In some cases they can be linked with other conditions in the eye, eye trauma, or a baby being affected by an infection whilst developing in the womb.

Bilateral cataracts (in both eyes) often run in families which a baby might inherit. Up to 23 per cent of congenital cataracts are inherited. They can also be linked with other conditions or infections, such as rubella, when the baby was growing in the womb. Medical conditions that affect the baby’s metabolism (how its body turns food into energy) can also cause congenital cataracts.

If a cataract is passed on to a baby from one or other parent it is usually dominantly inherited. One parent may know that they have cataracts themselves but sometimes they may only have a tiny cataract which does not affect their vision and which they are unaware of. This is why it can be helpful for the ophthalmologist to examine the eyes of the parents of a child with cataract even if they are unaware of a problem with their eyes.

Most children who are born with or develop infantile cataracts do not have other medical problems but some do. If an ophthalmologist is concerned that a baby may have other health conditions they will arrange for an examination from a paediatrician (a child specialist).

Cataract and visual system development

Visual system development and amblyopia

The visual system, that is the way the eye and brain work together, goes on developing up until your child is around seven or eight years old. The visual system is stimulated and developed by using your vision. If a child is born with an eye condition which affects vision such as cataract, then their visual system may not develop normally. This is because a cataract lowers the amount of visual stimulation the eye and brain receive.

If one of your child's eyes is sending poorly focused, unclear images to their brain, their brain will learn to ignore these images in favour of those provided by the "stronger" eye. This prevents the visual system from developing properly in the "weaker" eye. This is known as amblyopia or lazy eye. Amblyopia may result in permanent visual loss in one eye.

Unilateral cataracts

With unilateral congenital cataracts the brain tends to rely on the eye without a cataract and learns to switch off from the eye with the cataract and reduced vision. In these cases it can be difficult to encourage the visual system to develop in the eye with the cataract.

Bilateral cataracts

If a child has bilateral cataracts the visual system will still develop, but it would be limited and might result in some vision being lost permanently. Bilateral cataracts can cause amblyopia to develop in both eyes.

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At birth

If the paediatrician or paediatric nurse suspects that your child has a congenital cataract at birth they will arrange a referral to an ophthalmologist (eye doctor) for a full examination of their eye and lens. An ophthalmologist would carry out this examination at hospital.

All babies in the UK are screened for eye problems including congenital cataracts within the first 24-48 hours after birth as part of the National Screening procedure. Babies are normally checked again by a health visitor around six weeks of age. If you are concerned about your baby's vision it would be important to discuss it with your health visitor. If your health visitor notices any signs of a possible eye problem or cataract they would refer your baby to a hospital ophthalmologist for a full examination.

Later in childhood

If cataracts develop later on in childhood there may be noticeable outward signs if they affect vision. For example sometimes a child may appear to have difficulty focusing on certain objects or has to hold their head at a certain angle or they may develop a squint. If you are concerned at any stage that your baby or child is not seeing normally, you should discuss this with your family doctor. Your GP would assess your child's eyes and would refer your child to see an ophthalmologist.

Examining the eye

Usually the ophthalmologist would put some dilation drops into your baby's eyes to make their pupil larger. This allows more light into the eye so they can see the cataract more clearly.

An ophthalmologist would normally use an instrument called an ophthalmoscope to examine the inside of your child's eyes. The ophthalmoscope is held close to the eye but will not touch it.

Sometimes a child will be given a general anaesthetic to allow the ophthalmologist to carry out an eye examination. This allows the doctor to look thoroughly at your baby’s eye whilst he or she is still without causing any distress.

In only a few cases would a cataract change the appearance of an eye. A very dense cataract can cause a child’s pupil to look white as the cloudy cataract can be seen through it. However, there are other causes of a "white pupil" which would need to be checked as an emergency as they can be serious.

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Considering surgery

Some cataracts do not cause visual problems and surgery would not be needed. If the cataract does affect your child's vision surgery will usually be considered to remove the affected lens from the eye. Once a cataract is removed it cannot grow back.

If your child’s cataract or cataracts are likely to have a significant effect on their vision and the development of their visual system, surgery may be considered under the age of three months. If your child only has a cataract in one eye then surgery may be considered under the age of six weeks. The specialist will discuss the options with you and what treatment might give the best results. They will discuss both the risks and benefits of surgery with you before any decision is made.

During surgery

During surgery, a small opening is made in the side of the cornea at the front of the eye through which the cloudy lens is removed using suction. Usually you and your baby will stay at the hospital for a few days so the hospital can make sure they are recovering well and show you how to care for their eye.

Lens replacement used in surgery

Once your child's natural lens and cataract has been removed, it may be replaced by a plastic lens placed inside the eye called an intraocular lens or IOL. If a lens implant is used during surgery it will last for life and usually does not need replacing. If your child is very young then the consultant may recommend using a contact lens rather than an implant. This is because contact lenses are not implanted into the eye so they are much easier to change or remove if necessary. In these cases an IOL is often implanted in a separate surgical procedure when a child is a bit older and their eye more developed.

When your baby is born, their natural eye lens is very round and more powerful than in adulthood. The power of your baby's lens and the lengthening of their eye from front to back (axial length) changes rapidly over the first few years of their life. This means that the power of an IOL used at a very young age may not be right for them as they get older, which can cause short sightedness (when distance vision is not focused properly). However, leaving a child without an eye lens (called aphakic), and using a contact lenses and/or glasses to correct vision can cause long sightedness (when near to/reading vision is not focused properly).

An IOL is often used during cataract surgery for older children, but may not be appropriate for a very young child, especially under the age of two. The ophthalmologist would discuss with you the possible risks and benefits of using an IOL for your child. They would take into account both your child's level of vision and their age.

Most children will have lens implant surgery at some point to ensure their vision develops as well as possible and to prevent, or minimise, amblyopia.

Your child's ophthalmologist may also consider patching your child's stronger eye to help their brain switch onto the weaker eye.

Glasses and contact lenses

After cataract surgery, children usually need glasses or contact lenses. This is because the artificial lens implant or contact lens used to replace your child's natural lens has a fixed focus. This means it can't change shape to focus clearly both near to and in the distance as our natural eye lens can. Glasses will help make sure your child can see as clearly as possible at all distances.

A number of children who have cataracts which don't need removing will need to use glasses and contact lenses.

Glasses and contact lenses will help to give your child the best vision possible. Your child might need a pair of glasses or contact lenses which correct either their near to or distance vision. Or they may need bifocal glasses or lenses where the top section of the lens corrects distance vision and bottom part of the lens corrects near to vision. Depending on the age of your child the hospital would teach them how to use such lenses.

The hospital specialists can usually provide the right glasses or contact lenses for your child. They will also show you how to put the lenses in and take them out of your child's eye or eyes so you can feel confident doing this at home. If your child is under the age of one, the hospital may wish to monitor their eyes every two to three months to check how well they are focusing.

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After cataract surgery

What to expect

Following the operation your child's eye will be a bit painful for 12-24 hours. The hospital will give you eye drops to put in your child's eye every two to four hours which will help to prevent inflammation or infection. After cataract surgery you will usually need to put eye drops in your child's eye for a month or two to help the healing process. The hospital will also give a medicine or tablet to help with pain relief.

The doctors will monitor post-surgery recovery and check on progress. They will also advise you how to use any medication.

Looking after your child's eye(s)

The nurses will show you how to put drops into your child's eye before he or she is discharged from the hospital. They will also go over any post-operative care techniques, such as bathing your child, wearing a plastic eye shield, or keeping the eye clean without wiping inside the eye or washing it out.

It is important to protect your child's eye and keep it clean following surgery, including being careful not to get dirty water or shampoo in the eye. This is to give their eye the best chance of recovery and to minimise the risk of infection. It also helps your child to feel as comfortable as possible.

The hospital may provide an eye shield to place over your child’s eye especially at night. This helps to protect the eye as a shield can usually stop your child from rubbing their eye whilst it is healing from surgery. The hospital staff would tell you when and for how long to use the shield. The hospital staff would normally give you a sheet of instructions on how to look after your child's eye whilst they are recovering from cataract surgery.

Possible complications after surgery

After surgery a small number of children may develop an eye complication such as:

Glaucoma. Problems with a build up of eye pressure which can usually be managed with eye drops but in some cases may need surgery to treat.

Eye infection. Antibiotic drops normally safeguard against infection. If a serious and rare eye infection called endopthalmitis develops then it can threaten sight in that eye. However, usually this kind of serious infection can be detected and treated.

Retinal detachment. If the retina detached from the back of the eye surgery would be given as soon as possible to put the retina back in place.

Strabismus (squint) can develop if the eyes are not working properly together. Glasses, patching, and occasionally surgery can be given to help.

Amblyopia (lazy eye) (which is also mentioned earlier in this factsheet). Amblyopia can develop when the brain switches off from the eye with worse vision and just switches on to the eye with the better vision. Glasses and patching can help.

  • Patching the stronger eye encourages your baby to use their weaker eye which is known as occlusion therapy.
  • Your child's "stronger" eye may be patched for several hours a day in early childhood.
  • Patching aims to encourage  your baby's visual system in the ‘weaker’ eye to develop.
  • If the consultant’s patching advice is strictly followed the better the chance of your baby developing the best vision possible in the weaker eye.
  • The specialist may advise you to patch your baby's stronger eye even if they have not had cataract surgery. If your baby's cataract is not dense or large enough to be removed by surgery patching the stronger eye can help your baby's brain to switch onto the eye with the cataract.
  • Sometimes drops can be put in the stronger eye to blur vision rather than wearing a patch or if wearing a patch isn't possible.

The orthoptist at hospital will be able to advise on the various ways to help a child to develop their vision as much as possible, such as glasses and patching.

The hospital specialist will monitor your baby's eye very carefully after surgery. This will include checking the health of your child's eye(s) and the focusing power of the eye. If your baby develops a complication the ophthalmologist can often treat it and will try to save as much sight as possible. The chances of your baby developing a complication are usually low. Complications are more common when a child has cataract surgery before they are 12 months old. If your baby has cataract surgery before they are 12 months old, your hospital specialist will see them more frequently for regular checkups. This is because glaucoma can develop in 10 per cent of babies who have surgery very young.

What to look out for

If you notice any swelling, bleeding, a lot of stickiness, redness in or around your baby's eye, or if they seem to be in pain after surgery contact the hospital immediately, or go to A&E, so your child can be seen quickly.

These complications can often be treated successfully if they are caught early enough. If you have any concerns about your child’s eye or post-operative care, contact the hospital where the surgery took place. Parents and carers will often be given 24 hour contact details before leaving the hospital.

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With early detection and treatment many children with congenital cataracts in the UK go on to have a good level of vision for the remainder of their lives. Once the cataract or cataracts are removed they cannot grow back and affect vision again. Many children with congenital cataract will be able to attend mainstream school, read, play and go on to live full lives.

It is important for your child to continue to have regular eye checks with the hospital or with a high street optician. This ensures your child is wearing the right type and strength of glasses or contact lenses so their vision develops as well as possible. The hospital will advise you on how often your child should have an eye check.

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