Validity of visual data captured by a register of children with cerebral palsy

Abstract

Purpose: To compare visual data held by the Northern Ireland Cerebral Palsy Register (NICPR) with that collected prospectively as part of a survey of visual function in cerebral palsy (CP) by an optometrist.Methods: 90 subjects with CP (aged 4–15 years) were recruited via the NICPR to a population‐based study of visual function in CP. Objective measurements of visual function were obtained and compared with data held on the NICPR (Parkes et al., 2001). The NICPR captures cross‐sectional information at a specific point in time, usually at 5 years of age and records known visual impairment, use of glasses and classification of level of vision. Level of vision is recorded as either: ‘normal/near normal’ (equivalent to 6/18); ‘moderately impaired’ (6/18–6/60); ‘severely impaired’ (< 6/60); or ‘no vision’.Results: Classification of the subjects’ level of vision as described by the NICPR was available for 49 subjects (54.4%). Direct visual acuity and refractive error data were available for 82 (91%) and 89 subjects (98.9%) respectively. One‐way ANOVA demonstrated an association between visual acuity and the level of vision classified by the NICPR (p < 0.05) with those classified as having a visual impairment demonstrating poorer acuity. Chi‐squared analyses revealed no associations (p > 0.05) between clinically significant refractive errors (mean spherical, astigmatism and anisometropia) and whether or not the child wore spectacles at the time of data collection for the register.Conclusions: The NICPR holds a limited amount of information regarding visual status of children with CP, recorded at one point in time (approximately five years of age). The NICPR accurately reflected visual acuity status suggesting that the information held is both accurate and that visual acuity is relatively invariant beyond five years of age in this population. The lack of association between spectacle wear recorded in the register and presence of clinically significant refractive errors may suggest that clinicians need to be more proactive in detecting and correcting errors. It may suggest, however, that contrary to the typically developing visual system, refractive errors develop after five years of age in CP. Prospective data are not available to determine between these hypotheses but the data underline the need for thorough, early visual assessment in CP.