This has to be the most difficult question to answer, but the one that parents really want answered, so we’ll try.
The simple answer is that it could be anything from completely normal vision to really very little in the affected eye(s). The reality for most children with a unilateral cataract is normal vision in the eye without the cataract and poor vision in the eye that was affected. Most children who have treatment for cataracts in both eyes achieve partial sight. Many adults who have had single cataracts removed as children will be able to drive in the UK although there are some hoops to jump through for the DVLA to get there. Few adults who have had two cataracts removed as children will be able to drive in the UK, but very few will be totally blind either (no light perception).
In general, children who have had two cataracts removed have better vision in each of their eyes than the vision that children with one cataract are able to gain in their affected eye, but children with one cataract will usually have much better overall vision because of their unaffected eye. Not all cataracts are best managed by their removal with a surgical operation. The lens of the eye cannot be ‘cleared’ with any treatment with medicines, diet or even lasers. As ‘cataract’ just means that part of the lens is opaque (cloudy) this may only be a small portion of the lens (e.g. anterior polar) or just scattered speckles in the lens (pulverulent) or wispy rings of haze (lamellar). Many individuals with partial cataract will develop good eye sight without surgery though some will require glasses. In the case of many children with lamellar cataract, as the lens of the eye adds new clear proteins the hazy portion is condensed in the central core (nucleus) and vision may slowly decline and surgery may be necessary to retain good sight. This often happens around 5 years of age.
The other thing that makes answering this question so difficult is the idea of ‘outcome’; medical studies might follow children for a few years, until they’re over 8, or until they are 18 years old. Very few studies follow patients for up to thirty years. People who’ve had cataracts removed as children can and often do have changes in their vision at any point during their lives. All of us want to know what’s going to happen to our child’s vision and it’s just about impossible to know that. Many of us think that this is one of the hardest things about bringing up a child with cataracts: if we knew what would happen it would be easier to prepare them well for adult life.
One (unilateral) cataract
If the cataract is found and treated early (before 3 months) or only develops later in childhood, you are able to do all the patching and there are no other problems with your child’s eye, there is a better chance of better vision. Some eyes still will still remain blind, or not develop very much vision even when everything goes well. A few children gain stereo or 3D vision and even perfectly normal 6/6 vision, but this is an exceptionally good result.
If the cataracts were nuclear, caused by PFV (persistent foetal vasculature, sometimes called PHPV), the eye is smaller than usual (microphthalmic), your child has other eye problems or learning difficulties, the cataract was found late, you don’t manage to do the right amount of patching or there are complications from the surgery, then your child has less chance of developing good vision in the affected eye. It’s not impossible that they can develop some useful vision and even quite a lot of vision, despite the odds, especially if you do the patching well.
Because one eye can make up for the work the other eye does very well, with a little loss of field of view and of 3D perception, there is very little that will be a problem in daily life for a person who only has normal sight in one eye.
Cataracts in both eyes (bilateral cataracts)
Virtually all children who have cataracts removed from both eyes will have a ‘visual impairment’ or VI, meaning that their vision cannot be corrected to normal, even with glasses / contacts lenses. In many cases this is not too far off normal vision though. A few adults who’ve had two cataracts removed in childhood may be able to drive, although the answer to the question every parent wants to know about whether their child will be able to drive is: probably not – until cars are better adapted for drivers with visual impairments.
Most children will go to normal mainstream school although the majority will need some extra support. Input from specialist teachers often starts before even nursery school giving advice to families on vision stimulation and on planning school placement. Support varies in different areas of the country and you may have a battle to get your child the right support in class and to make sure all their educational material is provided in a way they can see it. Having your child placed on the register of vision impairment may help you obtain an educational statement of needs and hopefully the support itself.
Most people who’ve had cataracts removed from both eyes as children will have visual impairment, and some will be able to register as sight impaired / partially sighted. Some will be able to register as severely sight impaired / blind. As sight may get worse as we age, the older the person is who has had the childhood cataracts, the greater the chance that they have a more severe visual impairment.
The things that reduce vision the most for people who’ve had childhood cataract surgery are:
- Amblyopia / Lazy eye (the brain not learning to see perfectly)
- Glaucoma (about 3 out of every 10 children who have the surgery at under 3 months of age develop glaucoma and this may cause a lot of vision loss)
- Retinal detachment (this usually happens years later)
Your child is more likely to have poor eyesight in the long term if the cataracts were of the ‘nuclear’ type, caused by PFV (persistent fetal vasculature, sometimes called PHPV), the eye is smaller than usual (microphthalmic), your child has other eye problems or learning difficulties, the cataracts were found late, or if they have a long lifespan.
Your child is more likely to have better eyesight if he or she had no other eye problems, learning difficulties or immediate complications from the surgery.
It may well be that newer treatments are better in the long term and obviously many expert specialists feel that they are, or they would not recommend them, but it will be impossible to say for sure until our children have grown up and grown older. Our guesses at what outcomes may be are based on information from people who’ve had older types of treatment, about which there are published studies so unfortunately they really aren’t a very reliable guide to what will happen to children who receive newer treatments.
Checked for medical accuracy by Miss Isabelle Russell-Eggitt, Consultant Paediatric Ophthalmologist, Great Ormond Street Hospital, London