Prenatal diagnosis of common genetic disorders.

that monocular occlusion helps to establish a fixed reference eye, which in turn leads on to improved reading.These authors discuss subtle eye movements and not difficulties in visual acuity, though these do occur and should be treated.Stein, Riddell, and Fowler used both the Dunlop test and a more complex synoptophore vergence test on 44 dyslexic children and 24 normal readers and found that two thirds of the dyslexic children were unable to make proper vergence movements when tracking small targets but were nearer to normal performance with larger targets.'In other studies they reported that poor readers without fixed reference eyes developed them after wearing an eye patch, with subsequent improvement in their reading.9Bishop reviewed the Stein and Fowler studies together with related work and concluded that many normal readers also have unfixed reference eyes as measured by the Dunlop test.9Performance on this test is strongly related to both chronological age and to mental age and so without controlling for these factors one cannot draw conclusions about causality.The findings on monocular occlusion are interesting, but a reanalysis of the data showed that the differences between treated and untreated groups dis- appeared and were no longer significant.9So where does this leave parents and general practitioners?Clearly the child with important reading difficulties will have to be referred for further investigations, but the doctor should provide a detailed history of the child's language development together with information on any history of language, reading, or spelling difficulties in other family members.Although they are not common causes of reading difficulties, it is always worth checking visual acuity and hearing.Children should be referred to educational or clinical pyschologists requesting a full psychometric assessment of intelligence, reading, and spelling.Parents should be encouraged to discuss the child's progress with teachers, but when this has already been tried without resolving the parents' concern the general practitioner or paediatrician should consider requesting the local education authority to undertake a full assessment under Section 5 of the 1981 Education Act.Far from "interfering" in the prerogative of educators the act lays a duty on NHS staff to draw to the attention of the local education authority any child whom they suspect of having "special educational needs."However the battles over dyslexia are resolved, one thing is certain- children who have major difficulties in reading and spelling certainly have "special educational needs.