Understanding. nystagmus. RCOphth

Transcription

1 Understanding nystagmus RCOphth

2 RNIB s understanding series The understanding series is designed to hep you, your friends and famiy understand a itte bit more about your eye condition. Other tites in the series incude: Understanding age-reated macuar degeneration Understanding cataracts Understanding eye conditions reated to diabetes Understanding gaucoma Understanding retina detachment Understanding retinitis pigmentosa A these eafets are avaiabe in audio, print and braie formats. To order pease contact RNIB s Hepine on (a cas charged at oca rate), emai hepine@rnib.org.uk or visit rnib.org.uk/shop. Three new tites are being added to the series: Understanding Chares Bonnet syndrome Understanding dry eye Understanding posterior vitreous detachment Visit rnib.org.uk/shop for more detais. 2

3 Contents What is nystagmus? Who is affected? What causes nystagmus? How common is the condition? How does nystagmus affect peope? What treatment is avaiabe? The good news How can the effects be minimised? Reated eye conditions Usefu contacts

4 What is nystagmus? Nystagmus is an uncontroed movement of the eyes, usuay from side to side, but sometimes the eyes swing up and down or even in a circuar movement. Most peope with nystagmus have reduced vision. Who is affected? Nystagmus that appears in the first months of ife is caed eary onset nystagmus or congenita nystagmus. The condition may aso deveop ater in ife when the term acquired nystagmus is used. What causes nystagmus? Nystagmus in eary chidhood may be caused by a probem with the eye or visua pathway from the eye to the brain. It occurs in a wide range of eye conditions of chidhood such as cataract, gaucoma, some conditions of the retina and abinism (see Reated eye conditions ater in this eafet). It may aso be found in chidren who have mutipe disabiities such as Down s syndrome. Many chidren with nystagmus do not have eye, brain or other heath probems. In this case the condition is caed congenita idiopathic nystagmus or idiopathic nystagmus, meaning that the condition starts very eary on in ife and the cause is unknown. 4

5 Severa types of nystagmus can be inherited. To find out the chances of someone passing on nystagmus to the next generation, a speciaist must first make an accurate diagnosis of the underying condition. A cinica geneticist can provide detaied information. Your eye speciaist wi be abe to refer you to one. Acquired nystagmus, which deveops ater in ife, may be a symptom of another condition such as stroke, mutipe scerosis or even a bow to the head. There are many causes. Nystagmus is not infectious or contagious. Because nystagmus may be the first sign of a serious disorder of the eye or the brain, it is vita that when nystagmus first deveops the chid or adut is referred to an ophthamoogist (eye speciaist) or a neuroogist. How common is the condition? Nystagmus is beieved to affect between 1 in 1,000 and 1 in 2,000 individuas. 5

6 How does nystagmus affect peope? Nystagmus affects peope in many ways and the effects vary from person to person. In amost a cases, vision wi be impaired. Here are some of the ways the condition can affect peope. Most peope who have had the condition since chidhood are not affected by a constanty moving image (known as osciopsia ), as their brain adapts to the movement of the eyes. However, peope who acquire nystagmus ater in ife are unikey to adjust so we and wi be affected much more by osciopsia. Nystagmus is often associated with reduced sight. The degree of sight oss varies from mid to very poor vision and can be reated to an underying condition if present. Many peope with nystagmus are eigibe to be registered as severey sight impaired/bind or as sight impaired/partiay sighted. Being registered as severey sight impaired/bind does not necessariy mean that you are totay without sight, or wi ose a your sight in the future. 6

7 Congenita or eary onset nystagmus does not usuay get worse over time. However, an underying eye condition may deteriorate depending on what it is and how it can be treated. Sometimes treatment of the underying condition may improve nystagmus, but usuay nystagmus is permanent. Nystagmus may cause vision to vary during the day and is ikey to be affected by emotiona and physica factors such as stress, tiredness, nervousness or unfamiiar surroundings. Peope with nystagmus may tire more easiy than other peope because of the extra effort invoved in ooking at things. Many peope with nystagmus can read very sma print if it is cose enough to their eyes. Some find a visua aid such as a magnifier hepfu. However, arge print materia shoud aways be made avaiabe and a written matter shoud be cear, especiay at schoo. It is very difficut to share a book because it wi probaby be too far away or at the wrong ange. 7

8 Peope with nystagmus may read sowy because of the extra time needed to scan. This shoud not be taken as a sign of poor reading abiity, but students or schoo chidren with nystagmus may need extra time to study and when sitting exams. Many peope with nystagmus use computers, as they can position screens to suit their own needs and adjust brightness, character size, and so on. However, some peope find it difficut to read computer screens for more than a few minutes. Experimenting with different coour combinations and using arge screens may hep. The ange of vision is important. Many peope with the condition have a nu point where the eye movement is reduced and the vision is improved. They wi often turn their head to one side to make the best use of their vision. Sitting to one side of a screen or backboard often heps. Chidren with nystagmus shoud be aowed to adopt the head posture which gives them best vision. Some peope with nystagmus nod their heads, probaby because the head movement compensates in part for the eye movement. 8

9 Depth perception is usuay consideraby reduced. This may sometimes make peope seem a itte sower or cumsier than norma. Baance may be affected, possiby because of poor depth perception, which may make it difficut to use stairs or cross uneven surfaces. Confidence may be reduced because of poor vision and maintaining eye contact may be difficut. Getting about can aso be affected, especiay in unfamiiar and busy surroundings such as supermarkets, raiway stations and airports. Crossing roads is more difficut too. Orientation (knowing where you are) and mobiity (moving from pace to pace safey) training can hep. Very few peope with nystagmus are egay abe to drive a car. 9

10 What treatment is avaiabe? Nystagmus cannot be cured but there are severa treatments which can hep. There is on-going research into nystagmus, detais of which can be found on the Nystagmus Network website, Gasses and contact enses do not correct nystagmus athough they may hep a itte and shoud certainy be worn to correct other sight probems. A chid or adut may be diagnosed as being short sighted (burred distance vision) or ong sighted (probems with near-to vision) as we as having nystagmus. Long or short sightedness occurs because the eye itsef is not exacty the right shape for focusing. The focusing probems can be corrected with gasses or contact enses, but the nystagmus wi sti affect the person s eyesight. Your optometrist (optician) coud discuss this in more detai with you. Very occasionay, surgery is performed to ater the position of the musces, which move the eye. The purpose of this is to reduce the amount the head has to turn to try and see better. However surgery cannot correct or cure nystagmus. 10

11 Researchers have expored ways of trying to reduce the nystagmus by making the patient aware of the eye movement and encouraging them to contro it. These techniques rey on visua and audio signas (known as biofeedback) to the patient. For exampe, the patient might isten to an eectronic signa, which goes higher when the eye movement is greater. Some peope have said that they benefit from this type of treatment. However, the evidence is not concusive and many questions remain unanswered such as: Do these techniques bring about a rea improvement in vision and do the possibe effects ast? The good news Nystagmus is not painfu and does not ead to progressive oss of vision. Probems resuting from congenita or eary onset nystagmus tend to improve unti vision stabiises around the age of five or six. Giving chidren penty of stimuation in the eary years does seem to hep them make best use of the vision they have. Toys which encourage the chid to foow a moving object, such as marbes or train sets, are hepfu. So are games which are designed to deveop hand-to-eye coordination. 11

12 It is not possibe to say which type of schoo is best for a chid with nystagmus each chid has their own specia requirements. However, most chidren with nystagmus go to mainstream schoos. Many go on to coege and most aduts with nystagmus ead independent ives. How can the effects be minimised? Much can be done to reduce the effects of nystagmus and make sure that peope with the condition have the same access to the same opportunities as fuy sighted peope. Accurate information and support, during the eary years in particuar, can and does make a big difference. In the worst cases, without a cear expanation of the effects of nystagmus, some chidren are mistakeny thought to have earning difficuties. This means that the rea probems caused by their poor vision are not addressed. With the support of teachers trained in visua impairment, an understanding schoo and the hep of parents, most of the difficuties presented by nystagmus can be overcome. It is important to remember that many chidren with nystagmus do not have eye, brain or other heath probems. However in a sma number of cases nystagmus can be reated to other conditions. 12

13 Reated eye conditions Abinism Abinism is the name given to a group of inherited conditions in which there is a ack of pigmentation (coour) in the eyes (ocuar abinism) and often in the skin and hair as we. This causes most peope with abinism to have a very fair, amost white, appearance, athough in some peope abinism affects the eyes ony. Peope with abinism find their greatest probems arise on sunny days and in brighty it environments. Virtuay everyone with abinism has nystagmus. Cone dystrophy Cone dystrophy is an impairment to vision which can be caused by any one of a number of eye disorders. These disorders may or may not be inherited. Some dystrophies appear ater in ife, sometimes as ate as 50. Other types may appear in eary chidhood or even be present at birth. Cone dystrophy affects centra vision and can cause probems with seeing in bright ight, seeing detai such as watching TV, reading, writing or sewing and seeing coours. 13

14 Chidhood (or juvenie ) cataract Cataract is a couding of the ens of the eye which causes sight to become burred or dim, because ight cannot pass through to the back of the eye. Not a cataracts impair sight so bady that an operation is required. Some babies are born with cataracts and some deveop them ater in chidhood. Chidhood cataract may be inherited or may be caused by injury or iness. However, in most cases the cause cannot be identified. Down s syndrome Down s syndrome is a genetic condition caused by the presence of an extra chromosome. Peope with Down s syndrome have 47 chromosomes instead of the usua 46. It is amongst the most common forms of earning disabiity. Peope with Down s syndrome can often have nystagmus and may have other eye conditions. They shoud have their sight checked reguary by an optometrist. 14

15 Usefu contacts Roya Nationa Institute of Bind Peope 105 Judd Street, London WC1H 9NE t: Nystagmus Network t: The two main aims of this nationa sef-hep group are to support a those affected by nystagmus and to encourage the search for a treatment and a cure. Services incude a teephone hepine, meetings, taks, bookets and a range of information eafets. Roya Coege of Ophthamoogists 17 Cornwa Terrace, London NW1 4QW t:

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18 Information sources We do a we can to ensure that the information we suppy is accurate, up to date and in ine with the atest research and expertise. The information used in RNIB s understanding series of eafets uses: Roya Coege Of Ophthamoogists guideines for treatment cinica research and studies obtained through iterature reviews information pubished by specific support groups for individua conditions information from text books information from RNIB pubications and research. For a fu ist of references and information sources used in the compiation of this eafet emai pubishing@rnib.org.uk or ca

19 RNIB Hepine If you, or someone you know, is iving with sight oss, we re here to hep. This eafet has been produced jointy by the Roya Coege of Ophthamoogists and Roya Nationa Institute of Bind Peope. RNIB and RCOphth RNIB reg charity no RCOphth reg charity no Printed February Review date August ISBN: PR10816