Subnormal visual acuity in children: prognosis and visual evoked cortical potential findings

Seventy-one children, age 4-12 years, with subnormal visual acuity (VA) in at least one eye (0.7 or less) were examined using visual evoked cortical potentials (VECPs) to pattern-reversal stimulation. Twenty-eight children with squint had mean VA 0.3 in squinting and 0.7 in non-squinting eyes. Thirty-one children had unexplained subnormal VA, mean 0.6. Twelve children with mild unclassifiable fundus abnormalities had mean VA 0.5. In the squinting eyes and the eyes with fundus abnormalities the mean latency of the VECP was significantly prolonged. In squinters the mean amplitude to stimulation of the squinting eyes and to binocular stimulation was significantly reduced. Statistically significant increase in the mean VA was observed in all groups except in the cases with visible fundus abnormalities. There was no statistically significant correlation between VECP parameters and final VA. In conclusion, VA prognosis could not be predicted from VECP data in individual cases.