A cataract is called congenital when it is present at birth. It is also known as 'infantile cataract' if it develops in the first 6 months after birth. It can affect one eye, which is known as 'unilateral cataract' or both eyes, which is known as 'bilateral cataracts'. Most children with cataract in only one eye usually have good vision in the other.
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, although this will depend on its size and how dense the cataract is. Very developed cataracts can cause blindness in babies if left untreated.
Congenital cataracts can continue to develop, although this normally takes months to years. The ophthalmologist (eye doctor) will take all this into account when considering treatment.
Causes of Congenital Cataracts
Cataracts form when the protein in the lens clumps together which produces a 'clouding' or frosted affect. There are a number of reasons for this, including hereditary factors, infection (such as Rubella during pregnancy) and metabolic disorders, but in the majority of cases cataracts are idiopathic, meaning they have no known cause.
Approximately 200 children in the UK are born with some form of congenital cataract every year. Around one fifth of these have a family history of congenital cataract.
Cataracts can be dominantly inherited - that is passed on from one or other parent to a child because of a faulty gene. The 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 (eye doctor) 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. This possibility will always be looked at by the ophthalmologist who will refer a child onto a paediatrician (a child specialist) if necessary. The majority of children with congenital cataract will be able to attend mainstream school, read, play and go on to live full lives.
Cataract and Visual System Development
The visual system, that is the route of communication between the eye and the brain, goes on developing up until around the age of 7. During this period of development the eye needs to produce a clear image otherwise the system will not fully develop.
If one eye is sending poorly focused, unclear images to the brain, the brain will learn to ignore these images in favour of those provided by the 'good' or '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.
With unilateral congenital cataracts the brain tends to rely on the eye without a cataract and learns to switch off from the eye with reduced vision. In these cases it can be difficult to encourage the visual system to develop in the eye with the cataract.
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.
Every baby needs to be screened within the first 24-28 hours after birth as part of the National Screening procedure. Babies are normally checked again by a health visitor around 6 weeks of age. If a parent is concerned at any stage that their baby is not seeing normally, they should discuss this with their family doctor.
If the obstetrician or hospital doctor suspects that a child has a congenital cataract they, will arrange a full examination of the eye and lens. An ophthalmologist (eye doctor) would carry out this examination at hospital. If a child's cataract or cataracts are likely to have a significant effect on the child's vision, surgery may be considered under the age of 3 months. In these cases it is very important to get a referral to an ophthalmologist as quickly as possible following diagnosis.
The ophthalmologist would normally use an instrument called an ophthalmoscope which allows them to examine the inside of a 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 a eye examination. This allows the doctor to look thoroughly at the baby's eye whilst he or she is still without causing any distress.
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. In these cases the GP will refer you to see an eye specialist.
In only a few cases would a cataract change the appearance of an eye. A very advanced 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.
Some cataracts do not cause visual problems and surgery would not be needed. If the cataract does affect vision, surgery will usually be considered to remove the affected lens from the eye.
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. A child will normally be kept in overnight so that the hospital can make sure they are recovering well.
Once the cataract lens has been removed, it may be replaced by a lens placed inside the eye (intraocular lens or IOL), although in most cases this does not happen and glasses or contact lenses will be required.
The consultant may recommend using a contact lens for a young child or baby rather than an implant. Because contact lenses are not implanted into the eye they are much easier to change or remove if this becomes necessary. Glasses and contact lenses will also often be worn by children who do not require or have surgery.
After cataract surgery
Following the operation the eye may feel slightly uncomfortable or itchy. The eye will be covered for a few days to help it heal and protect it. The hospital will provide you with eye drops which will help to prevent inflammation or infection, and are usually used for a month or two to help the healing process. Eye drops are used as soon as the dressing covering the eye is removed. This usually happens the day after the operation. If the eye seems to be uncomfortable, the hospital may also consider a pain reliever.
The doctors will monitor post-surgery recovery and check on progress. They will also advise on the use of any medication. The nurses will show parents or carers how to put drops into a 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 the 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 the eye and keep it clean following surgery, including being careful not to get dirty water or shampoo in the eye. This is to give the eye the best chance of recovery and to minimise the risk of infection
The hospital may provide an eye shield to place over the child's eye, especially at night. This helps to protect the eye as it can usually stop the child from rubbing it after surgery. The hospital would also say when and for how long the shield should be used. Patients or carers are normally given a sheet of post-operative care instructions which includes this kind of advice.
Later complications such as glaucoma, eye infection and retinal detachment may occur following surgery in around 2 per cent of cases. There is treatment available for these conditions and information is available from the RNIB.
Complications are more common when a child under the age of one has had surgery for congenital cataract. A child will have more frequent check ups in these cases.
If you notice any swelling, bleeding, a lot of stickiness, pain or redness in or around the operated eye, then prompt medical attention is required.
These problems 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.
Following surgery, vision in one eye may be better than in the other and patching might be necessary. Patching is when one eye is covered with a patch to encourage a child to use their other eye. The 'stronger' eye may be patched for several hours a day in early childhood. Patching aims to encourage the visual system in the 'weaker' eye to develop.
If the consultant's patching advice is strictly followed, the better the chance of visual system development in the weaker eye. patching may also be used in cases where surgery is not considered necessary, for example if the cataract is not considered to be dense or large enough to merit an operation. Sometimes drops can be put in the stronger eye to blur vision rather than wearing a patch.
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, eye exercises and patching.
Low Vision Services
Low Vision Services can help people make the most of their sight and are normally located within the hospital eye departments are usually accessed through a referral from the hospital eye consultant or GP.
- Offer a thorough assessment of vision and prescribe the appropriate magnifier for the individual.
- Provide training on how to best use the magnifier.
- Give advice on lighting which can be important in getting the most benefit out of the magnifiers.
- Give advice on maximising the use of peripheral vision.
Contact with the specialised education advisers will help a child to make the most of their school years. Most local education authorities have experienced staff who work with parents, children and teachers to help a child get the most out of their school years.
Many children with a visual impairment attend mainstream school and may have a peripatetic teacher to help or visit regularly to make sure they have been given all the aids and assistance needed to help them achieve their best.
Someone at work with sight problems may benefit from talking to the disability employment advisers at their local jobcentre. These advisers can give information, provide equipment and assess the individual's work place. They work with you and your employers to make any changes needed to remain in your present job. They are also experienced in providing information on training for a new career.