When a cataract is removed, the whole lens of the eye is removed. The job of the lens is to focus (bend) the light coming into the eye so that it makes a crisp image on the light-sensitive retina at the back of the eye. Once the natural lens is gone, your child will need an artificial lens to do its job. If the light entering the eye is not focussed, all they will be able to see is light and dark and colours and blurred shapes, rather than the detail of the world around them. It would be like opening your eyes and looking up at swimmers and lights above from the bottom of a swimming pool. There are three different ways of focussing the light; glasses (spectacles), contact lenses that sit on the surface of the eye and must be removed to be cleaned, and lens implants that are fitted inside the eye by a surgeon. Most children will use a combination of these to correct their vision.
Contact lenses + glasses
This is probably still the most common sort of visual correction after cataract surgery in children. There are different types of contact lenses that are fitted and the Optometrist will decide which is the most appropriate. They may be soft, rigid or silicone rubber materials. They all need to be put in every morning and taken out to clean overnight. Contact lenses can be difficult to put in although it gets easier with practice but it can be hard emotionally at first because of your child’s distress. It is easier to if two people are around initially, one to hold the child, and the other to insert the lenses into the child’s eyes. Very young infants usually take to lens wear quickly and easily.
Once your child is used to wearing contacts, they will usually be happy for them to be put in, as they know that they will be able to see clearly once it’s done. Many children learn to put their own lenses in and take them out from quite an early age.
Some parents who find taking the lenses in and out really tough may agree with their Ophthalmologist or Optometrist to leave their child’s lenses in for a few days at a time (although there’s a bigger risk of eye infections which can permanently damage the eye if they cause a corneal ulcer). The other alternative is that your child can wear spectacles instead.
You will be shown at the hospital how to look after your child’s lenses and how to put them in and take them out. For moral support, and helpful tips, our CCN eGroup the PGCFA and APHAKIC Yahoo groups are great.
If your child’s eye is ever red, sticky, watery, extra sensitive to light or difficult to open, take the lens out immediately and phone your ophthalmologist. If there is an infection of the cornea and your child continues to wear a contact lens this could lead to blindness as the infection can quickly spread inside the eye from a corneal ulcer, so you must get medical advice straight away.
Contact lenses are good because they give your child a normal field of view. In other words, they are able to see a wider area than with spectacles. Also, it is unusual for young children to wear spectacles and the aphakic glasses (those worn after surgery to remove cataracts) are quite thick and obvious.
Your young child’s contact lenses will be ones that allow the eye to focus within about 1 metre as that is where babies and young children spend most of their time looking. As your child looks further away, the objects will become less clear and distance vision will be a little blurred. When your child is older and starting to read, they will get bifocal glasses to wear as well as the contact lenses (the sort of glasses usually worn by older people) so that they can see things that are further away as well as things that are near.
Varifocals (where the focus changes gradually from top to bottom and there is no line) are not advisable for young children as they need to be precisely measured and stay in the correct position all the time in order to work properly. Older children and teenagers, especially if they feel self-conscious about their appearance, may benefit from varifocal lenses. Varifocals are not available on the NHS in all parts of the UK.
Implants + glasses
Implants or intra-ocular lenses (IOLs) are hard plastic lenses, about the size and shape of natural lenses, but with ‘arms’ to fix them in place that are fitted into the eye at the time the cataract surgery is done, or later. This is what most older people who have cataract surgery have done. They are now being used more and more often in babies and young children, but different surgeons have different opinions about when they are the best choice and when they are not. You might want to read our article on the IOL debate if you’re making a decision about whether this is the right treatment choice for your child.
When implants are fitted to a baby or a young child, the surgeon chooses a lens that should allow the eye to focus clearly when the eye is fully-grown. This means that the implant still leaves your young child’s vision blurred (but not as blurred as it would have been without it) so he or she will have to wear glasses all the time to correct the ‘deliberate mistake’ in the implant strength. These glasses can look very thick on a baby, but most children will be able to change them to thinner ones as the eyes grow. The eye has done most of its growing before a child reaches an age when they might feel more self-conscious so most children will be wearing very normal-looking glasses by that time.
Just as with contact lenses, at about school age, or perhaps before, your child will need bifocal glasses so that he or she can see things at different distances crisply.
Implants + contacts
This option is used in some children although the type of lens has to be carefully selected and soft lenses may be difficult to insert into the eyes of a squirming child as they are thin and easily folded (unlike the thicker lenses used without implants).
These are very thick glasses that do all the focussing work of the eye’s natural lens on their own. Years ago they were the only option. They are not usually chosen for children with just one cataract as the difference between the very heavy lens on one side and the very light lens on the other can be uncomfortable.
The good things about aphakic glasses are that they don’t increase the risk of eye infections as contacts do, nor do they need parents and carers to handle lenses. They don’t need surgery as implants do, and they’re very easy to change and for your child to put on in the morning. Children get used to them very easily and the visual development is just as good as with the other two options.
The natural lens of the eye has UV (ultraviolet) filters in it to stop UV light getting through and damaging the light-sensitive retina. After cataract surgery, your child’s eye will need extra UV protection, this should be built-in to implants and contact lenses, and can also be built into apahakic glasses. Your child is likely to benefit from a pair of dark aphakic glasses as well as it is impossible to get clip-on sunglasses that will fit over aphakic lenses.
Many children and adults choose to wear them sometimes as they may give the best vision for, say, looking at a blackboard, or to give their eyes a rest from contacts.
Aphakic glasses can be a bit heavy to wear and they look unusual enough for other people to stare. They also only allow your child to see clearly in the centre of their field of view so it might be that your child trips over things more while wearing them because they don’t notice the things under their feet – especially if you or they want to choose a modern ‘letterbox’ frame style.
They may be a good choice for a toddler who is fiercely resistant to having contact lenses put in, or where the parent’s visual impairment makes dealing with contacts tricky. It’s simple to switch between glasses and contacts when your child grows older and becomes more concerned that they don’t want to look different.
Aphakic glasses need to be made as bifocals for a child of school age, or sometimes younger so that your child can see things at different distances crisply.
Most children with cataracts are sensitive to light (photophobic). For some it can be a big problem, but it is not advisable to have a tint on the glasses for indoors. Your child may well need sunglasses, either as prescription sunglasses, dark over-glasses (available cheaply, the small adult size being suitable for older children from the RNIB shop, they are not listed in the catalogue but are also available on special order from Optima for younger children) or clip-ons, which can be very hard to find to fit aphakic glasses.
Photochromic glasses (the ones that go dark in the sun) can be a better option for children wearing glasses over their contact lenses or implants but they may not be available in the prescriptions needed for aphakic spectacles. You should take the advice of your child’s optometrist or ophthalmologist about when he or she should wear dark glasses. See our photophobia article for more information on this. Polarised lenses may also help reduce glare as can an amber or brownish tint rather than a greyish tint.
Checked for medical accuracy by Miss Isabelle Russell-Eggitt, Consultant Paediatric Ophthalmologist and Lynne Speedwell, Senior Optometrist, Great Ormond Street Hospital, London