Visual acuity and visually evoked responses in children with cerebral palsy: Gross Motor Function Classification Scale

Background/aims: Measurement of visual acuity can be difficult in children with cerebral palsy (CP). The purpose of this study was to determine the probability of obtaining quantitative (logMAR) visual acuities in CP children with different severities of motor dysfunction. Methods: An observational, cross-sectional design study was conducted in 76 children (mean age 5.9 years) who had CP severity graded using the Gross Motor Function Classification Scale (GMFCS). Visual testing was performed using optotypes, spatial-sweep (SSVEP) or flash (FVEP) visually evoked potentials. Results: LogMAR acuity was obtainable in 88% of CP children, using either optotypes or SSVEPs. The success rate decreased with increasing severity of GMFCS Levels 1–5; nevertheless, logMAR acuities were obtainable in more than one-half (56%) of children with the most severe disease: Level 5. Similar results were obtained for CP severity assessed using physiological-anatomical subtype (hemiplegic; diplegic; quadriplegic) rather than GMFCS. The mean logMAR acuity (0.37; 20/48) in the CP cohort as a whole was ∼2 Snellen-equivalent lines worse than that recorded in age-matched, normal children (0.22; 20/33). Conclusion: Quantitative visual acuities can be obtained in the majority of CP children, including those with severe motor dysfunction. Difficulties in testing CP children lead often to the misconception that the children have immeasurably low vision.