Main description:

Over the past few years there have been considerable advances in our understanding of the normal development of vision and in our ability to detect and meaSl1re visual impairment in early childhood. It was appropriate, therefore, that a workshop, sponsored by the European Communities, should be held on the 'Detection and Measurement of Visual Impairment in Pre-verbal Children.' This workshop, which was held at the Institute of Ophthalmology, London, between 1 and 3 April 1985, brought together visual physiologists and ophthalmologists who exchanged and discussed ideas of mutual interest. After an introductory session when the normal development of vision and the causes of visual impairment were reviewed, there were sessions devoted to the theoretical aspects of electrophysiological and psychophysical tests, the measurement of visual acuity in pre-verbal children, the measurement of other visual functions, and visual screening of pre-verbal children. This volume contains the papers presented at the workshop, and transcripts of the various discl1ssions that took place. It was a measure of the success of the workshop that participants from several different disciplines were able to have fruitful discussions and to suggest areas of common interest where collaborative ventures could usefully be pursued. It is hoped that this venture will be followed by others where a mul ti disciplinary approach will improve both our knowledge of visual handicap in childhood and our management of this important group of sensorily impaired children.

Contents:

Session I - Normal Development of Vision and Causes of Visual Impairment.- Organisation, development and early manipulations of primate's visual pathways.- Ocular growth and the normal development of vision: clinical aspects.- Genetic causes of visual impairment in childhood.- Non-genetic causes of visual impairment in early childhood.- The changing aetiology of visual impairment in early childhood in Greece.- Discussion.- Development of vision in visually impaired children.- Definitions of visual impairments and their consequences in infants and small children.- Discussion.- Session II - Electrophysiological and Psychophysical Tests - Theoretical Aspects.- Theoretical aspects of the pattern ERG.- Identification of first and second order Volterra kernels for the human electroretinogram.- Discussion.- Pattern VEPs in very young infants.- VER testing of cortical binocularity and pattern detection in infancy.- Discussion.- Session III - Measurement of Visual Acuity in Pre-verbal Children.- Visual function in the newborn infant: behavioural and electrophysiological studies.- Discussion.- Development of separation-ability of contours during childhood: quantification of the crowding phenomenon in amblyopia.- Measurement of visual acuity in young children by a new instrument: Casimir.- Discussion.- Evaluation of electrodiagnostic tests in children.- The pattern reversal ERG and its application to the measurement of infant visual acuity.- Discussion.- Measurement of visual acuity in infants and young children by visual evoked potentials.- Discussion.- Comparison of rapid procedures in forced choice preferential looking for estimating acuity in infants and young children.- Visual crowding in young children.- The development of preferential-looking visual acuity in human infants: a correlation with animal models.- Preferential looking acuity in normal and neurologically abnormal infants and pediatric patients.- Preferential looking for the detection of early amblyopia and monitoring early therapy.- Discussion.- Computer assisted evaluation of visual functions in non verbal children.- Discussion.- Visual acuity assessment with preferential looking1 in young children treated for opacities of lens and vitreous: a longitudinal study.- Refractive changes and retarded visual development in aphakic children after operation for congenital cataract.- Discussion.- Albinism: an anomaly of maturation of the visual pathway.- Discussion.- Session IV - Measurement of Other Functions.- Objective evaluation of binocular cooperation in normals and strabismics by means of visual evoked responses.- Discussion.- Dark adaptation assessment in childhood, especially early childhood (review).- Discussion.- Visual field measurements, optokinetic nystagmus and the visual threatening response: normal and abnormal development.- Discussion.- Nasal field defects in strabismic amblyopia.- Discussion.- Apparent blindness due to saccadic paralysis or delay.- Discussion.- Session V - Screening of Pre-verbal Children.- Experience with our present screening program.- Early detection of visual disorders in health centres in young children.- Discussion.- Problems of screening and its implications to the orthoptic service in West Berkshire.- Discussion.- Rapid assessment of visual acuity in infants and children in a clinical setting, using acuity cards.- To what extent is it possible to quantify monocular or binocular visual impairment in pre-verbal children? Role of clinical signs and of electrophysiological and psychophysical testing techniques.- Population vision screening and individual visual assessment.- Discussion.- Final Discussion.