A cataract is cloudiness in the lens of the eye. This means the lens is no longer transparent. The lens is located behind the iris (the coloured part of the eye), and focuses light rays on to the retina. The retina is the inner layer at the back of the eye. For a child to be able to see, light has to pass through the transparent lens to the retina.
In a normal eye the cornea and the lens focus light rays onto the retina.
Lens with a cataract, blocking the light rays so the eyesight is reduced.
Cataracts can occur in one or both eyes. What causes most cataracts is unknown. We do know that some cataracts are linked to metabolic and infectious diseases (like rubella) and some syndromes. In most cases, the cause cannot be identified. About one third of cataracts are hereditary. For example, the child's grandparent or parent may have been born with a cataract. The parent and child usually have a cataract in the same part of the lens, as well as the same type of cataract.
Most cataracts are invisible until they became dense enough to cause a loss of sight. When the lens becomes cloudy it thickens and the pupil appears white. Congenital cataracts can vary in density. If the cataract is not dense enough to interfere with vision, it may not need treatment. The Ophthalmologist (eye doctor) and Orthoptist (eye therapist) will continue to monitor your child. If the cataract reduces your child's vision, the cloudy lens will be removed.
Some of the symptoms of cataracts
- Glare - the same effect as car headlights through a dirty windscreen at night.
- A white pupil known as leukocoria - this is due to the cataract showing through the pupil. The pupil is just a hole or opening which allows light to enter the eye.
- Poor vision - light is not getting through the lens, because it's no longer transparent.
- An eye turn may develop. This is called strabismus, or squint. A “turn” occurs because the eye can not focus properly.
To diagnose the congenital cataract, the Ophthalmologist will examine your child's eyes with an instrument called an ophthalmoscope. Before the examination, the pupils of the eyes have to be dilated with eye drops in order to view the lens and retina properly.
If your child needs surgery
Cataracts are usually treated by surgically removing the lens of the eye. The lens is removed by making a small incision in the eye. The operation usually takes about an hour. Your child may either stay for the day or may have to stay in hospital overnight. Your child will return to the ward with an eye pad covering the operated eye. This pad will be removed the next day. Not all cataracts need surgery.
After the operation
After the operation, your child will need eye drops frequently during the day for a period of time. You will be seen by the doctor after the surgery. At that appointment a contact lens or glasses may be prescribed. Your Orthoptist will arrange a contact lens teaching session where you will be shown how to insert, remove, clean and care for your contact lens. In some cases an intra-ocular lens (a lens implanted in the eye) may be placed in the eye at the time of surgery. It may also be inserted when your child is older during a second operation. Not all children with congenital cataract will have an intraocular lens inserted.
Contact lenses are usually the preferred choice for treating aphakia (an eye without a lens) in children with cataracts.
Vision development and patching therapy
Your child’s vision develops quickly in the first few years of life and continues to develop up until the age of eight. It is important that children with congenital cataract have their vision checked regularly during these years. Some children will also need patching therapy for amblyopia (lazy vision) that is caused by the cataract. Your Ophthalmologist and Orthoptist will discuss if this is needed for your child with you.
- Cataracts are usually treated by surgically removing the lens of the eye.
- Your ophthalmologist will prescribe contact lenses or glasses.
- Your Orthoptist and ophthalmologist will monitor your child’s vision and decide if patching therapy is needed.
- Some children will have an intraocular lens inserted.