One of a series of leaflets available from the Down's Syndrome Association Down's Syndrome Association Medical Series 6. EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME Notes for parents & carers Accessible resources for people with learning disabilities and visual problems can be obtained from The RNIB Multiple Disability Team, RNIB, 224 Great Portland Street, London W1N 6AA Telephone: 020 7388 1266 Fax: 020 7388 2034 EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME The eye problems which may affect children with Down's syndrome are commonly those which occur in any group of children ­ they just tend to occur more frequently and sometimes to a more marked degree. Health Visitors and General Practitioners will arrange for the children in their care to have their eyes checked and this is even more important if a child has Down's syndrome. The treatment of children with Down's syndrome usually differs very little from that of other children. Because of their learning difficulties children with Down's syndrome sometimes do vision tests designed for younger children. They may find it easier to sign rather than name pictures verbally. Children. with a heart condition do not usually have a problem if they need eye surgery, but advice from the cardiologist should be sought. 1 Down's Syndrome Association. www.downs-syndrome.org.uk Down's Syndrome Association Medical Series 6. EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME. Notes for parents and carers Updated 2001 COMMON EYE CONDITIONS SQUINT Around 20% of children with Down's syndrome have a squint. A squint is when the eyes are pointing in slightly different directions. Squints can be intermittent especially when they first appear; others are constant. In some cases the child alternates between squinting with the right eye and the left eye; in others, the child squints constantly with the same eye. When one eye moves out of alignment the brain receives two separate images so the one from the squinting eye is suppressed. The vision in a constantly squinting eye tends to be reduced. Many children squint because they are long-sighted or short-sighted and consequently need glasses. Many children with a convergent squint, where one eye turns inwards towards the nose, are long-sighted (hypermetropic) and often, if such a child is given glasses to correct this the squint can become less noticeable or even disappear completely while the child is wearing the glasses. Children who are short-sighted, or who are likely to become short- sighted when they grow older, may have a tendency for one eye to drift outwards which can be controlled. If any child is suspected of having a squint or any visual problem, it is important to arrange referral to someone who can establish a diagnosis and arrange treatment. Usually, children see an orthoptist, who always works closely with an ophthalmologist and possibly an optometrist (see box). PEOPLE WHO SPECIALISE IN EYE CONDITIONS An ORTHOPTIST is specially trainedin the assessment of vision in people of all ages and all abilities, the recognition of squints and disorders of eye movements and the treatment of squints and related disorders. An OPHTHALMOLOGIST is a doctor specialising in eye conditions. An OPTOMETRIST is trained to test for glasses and other aspects of visual function and to recognise ocular abnormalities. They are also able to dispense glasses. A DISPENSING OPTICIAN is trained to fit spectacle frames and arrange to have these made up with the appropriate measurements and lenses for individual people. 2 Down's Syndrome Association. www.downs-syndrome.org.uk Down's Syndrome Association Medical Series 6. EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME. Notes for parents and carers Updated 2001 Often it is more difficult to recognise a squint in children with Down's syndrome because of the distinctive appearance of the eyelids. For this reason, it is desirable for all children with Down's syndrome to have routine screening as recommended in the Down's Syndrome Medical Interest Group Health Check Guidelines* (see below). GPs and sometimes Health Visitors can arrange an appropriate referral. Birth to 6 6-10 months 12 months 18-30 months 3-3½ years 4-4½ years weeks Eye check Visual Visual Visual Orthoptic Visual actuity, behaviour. behaviour. behaviour. examination, refraction and Check for Check for Check for refraction and ophthalmic congenital squint. squint. ophthalmic examination. cataract. examination. From age 5 to 19 years, vision orthoptic check should be made every 2 years. Treatment of Squints Firstly, the child must be carefully examined t o make sure that both eyes are healthy and to determine whether glasses are needed. This is usually done by putting drops into the eyes. These dilate and fix the pupil of the eye and make it possible to test accurately for glasses and examine the back of the eye with a light with only minimal co-operation from the child. The drops used nowadays to dilate the pupil do not contain atropine. Previously, people had sometimes worried about using atropine drops on children with Down's syndrome. Atropine drops are rarely used on any children and should be avoided. The second aspect of treatment is to make sure that the child has equally good vision in both eyes. An experienced orthoptist will be able to establish this and treat younger children who have reduced vision in one eye. This is often done by covering the eye which can see well for a period of time each day to improve the vision in the squinting eye. The orthoptist aims to produce equal vision in both eyes so that the child is able to use either eye to fix on a test target picture. Thirdly, if the child has a noticeable and unsightly squint, even when wearing glasses, then surgery can be arranged to correct this. At operation the position of the small muscles on the outside of the eye is adjured so that they pull the eye into a straighter position. * PCHR Down's syndrome © DSMIG 2000. 3 Down's Syndrome Association. www.downs-syndrome.org.uk Down's Syndrome Association Medical Series 6. EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME. Notes for parents and carers Updated 2001 LONG-SIGHTEDNESS (HYPERMETROPIA) About 40% of pre-school children with Down's syndrome are long-sighted. This is often associated with a convergent squint These children have to use extra effort to focus their eyes and this is more of a problem for close vision. If one eye is markedly more long-sighted than the other, the vision in this eye might be reduced (a lazy eye) and might require treatment from an orthoptist. SHORT-SIGHTEDNESS (MYOPIA) About 14% of pre-school children with Down's syndrome are short-sighted and the condition becomes more common up to adolescence. These children can often see near objects but have a problem with distance vision. ASTIGMATISM About 30% of pre-school children with Down's syndrome have astigmatism. This means that the image seen is distorted because the image is more out of focus in one direction than the other. The astigmatism can be either long-sighted or short-sighted or a mixture of the two. NYSTAGMUS About 10% of children with Down's syndrome have nystagmus. Nystagmus is a condition where the eyes make small, involuntary, jerky movements. Often these movements are more noticeable when the child is looking sideways. Sometimes there is a position of gaze where the movements are considerably reduced. If this is the case, the child might adopt a compensatory head posture which allows the eyes to be in a position in which the nystagmus movements are minimised. If this happens the child should not be discouraged from adopting the head posture as this is likely to be the position where the vision is at its best. The vision is often better for near than distance. Children with nystagmus often prefer to hold books very close as this improves their vision and they should be allowed to do this. EYE INFECTIONS Eye infections and watering eyes tend to be more common in people with Down's syndrome. Normally, tears, which are formed continuously to keep the eyes moist and healthy, drain down the naso-lacrimal duct which connects the corner of the eye with the back of the nose. In people with Down's syndrome, this tube is often quite narrow and so it easily becomes blocked. This leads to watering of the eye. As clean tears are not rinsing through the system so effectively, it is easier for infections to occur. Infections are usually treated with antibiotics 4 Down's Syndrome Association. www.downs-syndrome.org.uk Down's Syndrome Association Medical Series 6. EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME. Notes for parents and carers Updated 2001 given in the form of drops by day and ointment at night. If, however, the eyes are only slightly sticky and the discharge is not yellow or green, then bathing the eyes with cooled, boiled water in the morning and at night is usually sufficient treatment. Children may grow out of this problem as the face grows bigger and the duct grows wider. If infections persist, it may be necessary to probe and syringe the tear ducts. Although this is a minor procedure, it is carried out under a general anaesthetic in young children. As children with Down's syndrome often have rather dry skin they also tend to suffer from blepharitis. This is a condition affecting the eye lids where the skin around the eyelashes becomes flaky and inflamed. Usually the condition is mild and responds to simple measures such as bathing the lids with plain boiled water which has been cooled to a comfortable temperature. Sodium bicarbonate (a teaspoon to a pint of water) can be added. In more severe cases baby shampoo (normal shampoo would sting) can be used, in solution to clean the lid. Regular lid cleaning reduces irritation and lessens the likelihood of infections which would need to be treated with antibiotics. CATARACTS A cataract is when part or all of the lens of the eye has become cloudy. If the affected area is small it is possible to see round it, through the clear part of the lens. This kind of cataract does not cause a significant problem and is relatively common in people with Down's syndrome. A denser opacity of most of the centre of the lens is fortunately much less common as it causes a marked reduction in vision. Less than 1% of children with Down's syndrome have a dense cataract. These can be treated by removing the lens of the eye under general anaesthetic. As this leaves the eye unfocused, older people can have a lens implant at the time of the operation. Children often have an operation which makes it possible to have a lens implant inserted at a subsequent operation when the eye has reached adult size. If a lens implant is not inserted, the eye needs to be focused either by wearing thick glasses or contact lenses. Cataracts can be present at birth or develop later. They would be discovered at a routine check. KERATOCONUS This condition of the cornea (the clear structure covering the front of the eye) is more common in people with Down's syndrome but is still relatively rare. I have only seen one mild case in a child. The cornea, instead of being the normal curved shape, becomes conical. During the early stages this makes the person short-sighted, often with marked astigmatism 5 Down's Syndrome Association. www.downs-syndrome.org.uk Down's Syndrome Association Medical Series 6. EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME. Notes for parents and carers Updated 2001 making the vision distorted. Many cases do not progress any further than this stage. Other cases go on to develop scarring in the centre of the cornea. A smaller number develop sufficient thinning of the centre of the cornea to make them require a corneal graft. This is carried out under general anaesthetic. After a corneal graft the eye is vulnerable until it is completely healed. This can present some problems in people with Down's syndrome as the patient has to be discouraged from touching the eye. Fortunately, the more serious eye conditions are quite rare and, although the more routine eye conditions are relatively common, they are improved by treatment, especially if they are discovered early due to vigilant screening. QUESTIONS OFTEN ASKED BY PARENTS Q: When should a child with Down's syndrome first have an eye test and how often should this be repeated? A: If a child starts to squint she should be referred for an eye test as soon as possible. For children with Down's syndrome without any obvious problem, I recommend screening between 1 year and 18 months and again at the age of 4 years, prior to starting school. The children should have an assessment by an orthoptist, a test for glasses using drops and careful examination of the eyes. During the school years the children should be checked regularly at least every 2 to 3 years. If any disorder is found, the children are usually seen more frequently, often once or twice a year. This assumes that the child will also have developmental checks by a paediatrician who would also refer her if a problem were suspected. Q: How do you test vision at different ages? A: Babies can fix and follow a light or small toy. They tend to look at more interesting things when given a choice. A series of tests have been devised which give a choice between either plain grey and a striped pattern or between plain grey and the outline of an object. The person carrying out the test has to watch where the baby chooses to look. The test cards are graded to show finer and finer stripes or fainter and fainter pictures which are shown until the baby shows no definite preference. This is noted and compared with standards expected for babies of different ages. Other tests are used which involve rolling standardised balls of various sizes across the floor and watching the baby's eyes following each one. 6 Down's Syndrome Association. www.downs-syndrome.org.uk Down's Syndrome Association Medical Series 6. EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME. Notes for parents and carers Updated 2001 Toddlers are usually tested by showing them standardised black and white pictures held a measured distance away (Kay pictures) and asking them to name them. Some children with Down's syndrome prefer to sign to identify them rather than sag what the pictures show. Many children with Down's syndrome of three or four can be tested by showing that they can match letters. The child is given a card with five letters on it. The examiner shows a series of cards with letters of graduated sizes and the child points to a matching letter on the card he is holding. This test is carried out at an exact distance (6 metres). Each eye can be tested separately by covering one eye at a time. Slightly older children can use the matching card to identify letters on a line on the normal test type and this is even more accurate. Q: How is it possible to determine how strong glasses need to be in a young child? A: Small children are usually tested after drops have been put in the eyes. The drops relax the focusing of the eyes. The examiner is then able to wave a beam of light from a kind of torch called a retinoscope across the child's eyes while holding a lens in front of the eye. The strength of lens needed to neutralise the movement of the light indicates the strength of lens required in the glasses. Most small children do not mind looking at the light for the short time it takes an experienced person to test them. Q: If my child needs glasses will it be difficult to make him wear them? How can I help him get used to them? A: It can be difficult at the beginning. It is a good idea to put on the glasses and immediately start an activity which the child enjoys such as looking at books or playing activity games. Television and videos are only helpful if an adult is sitting with the child to prevent him from removing the glasses. The child will associate the glasses with enjoyable activities and if he is sufficiently distracted will forget he has them on. It is vital that the glasses fit comfortably because a child will try to remove them if they are digging into the face of the back of the ear. If a parent has some glasses it sometimes helps if they wear them more of the time. Nursery school teachers and play-group leaders can be very useful allies. Once the child has got used to the glasses they often become keen wearers when they realise they can see more clearly. 7 Down's Syndrome Association. www.downs-syndrome.org.uk Down's Syndrome Association Medical Series 6. EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME. Notes for parents and carers Updated 2001 Q: If it is difficult to get glasses which fit properly can I get some specially made? A: Children with Down's syndrome often have tiny noses with very little bridge. Glasses have a tendency to slide down the face until the child is looking over the top of them. It is worth asking local parents which opticians take the most trouble to fit and adjust the frames to fit comfortably. Sometimes a frame with a dropped bridge is more appropriate. It is worth returning to the optician to have the frames tightened and skilfully bent back into shape at regular intervals. If a child is particularly difficult to fit a handmade frame can solve the problem. These are very expensive but hospital optometry departments can sometimes arrange for these to be made and absorb the additional cost. Q: Do I have to pay for my child's glasses or can I get them on the NHS? A: All children (under 19 in full-time education) and older people who are either unemployed or have a low income are entitled to a voucher which is meant to cover the price of a basic pair of glasses. The value of the voucher increases with stronger lenses. It is sometimes necessary to pay extra money, in addition to the voucher price, to get glasses which fit well and are comfortable. It is not worth getting very expensive or exotic glasses as the child could lose them or break them and will certainly grow out of them. No additional help is given to single or unemployed parents. Q: Can my child have two pairs of glasses - my child is always breaking or losing his glasses? A: Unfortunately, it is not possible to issue two vouchers at the same time. However, it is possible to issue a new voucher each time a child is tested. If a child attends the clinic or optician regularly it is likely that he will have had his previous glasses prescribed recently enough for them to make an acceptable spare pair. The cost of repairs can bc covered by a repair voucher issued by your optician. Q: Is it right to take my child to a high street optician o r should she see a specialist? A: It is desirable for all small children to attend a hospital clinic where they will be able to see a team of people - orthoptist, ophthalmologist and optometrist and possibly a specialised dispensing service. Once the child has been fully evaluated and any problems treated they are often only kept in the hospital service until they are mature enough to be discharged to outside opticians. The service given by these opticians depends not so much on the name ­ often they 8 Down's Syndrome Association. www.downs-syndrome.org.uk Down's Syndrome Association Medical Series 6. EYE PROBLEMS IN CHILDREN WITH DOWN'S SYNDROME. Notes for parents and carers Updated 2001 are one of a chain ­ but on the care and expertise of the individuals working there. It is worth following recommendations given by parents of small children and of children with special needs. Barbara Crofts Associate Specialist in Ophthalmology Updated 2001 9 Down's Syndrome Association. www.downs-syndrome.org.uk