A prospective study of children treated for retinoblastoma: cognitive and visual outcomes in relation to treatment.

PURPOSE: : To assess cognitive and visual outcomes in children treated for retinoblastoma. PATIENTS AND METHODS: A population-based group of 22 children treated for retinoblastoma were followed in a longitudinal, prospective study. Eleven children had unilateral tumours, all of which had been enucleated. The remaining 11 had bilateral tumours. Seven of these had undergone unilateral enucleation and local or external beam radiation to the other eye. Four children had been treated with local or external beam radiation only. Cognitive outcome and visual function was assessed at 4 and 6 years of age.
RESULTS: We found no general delay in cognitive or motor development at 4 or 6 years of age. Better cognitive capacities were found in the bilateral/irradiated retinoblastoma patients than in unilateral/non-irradiated patients. However, two of the irradiated children, both of whom had been treated at 1 month of age, performed below group mean. None of the children was totally blind. Three children were visually impaired due to tumours affecting the macular area in the remaining eye; another three had subnormal visual acuity but no macular pathology. A total of 14 children had been enucleated and had normal vision in the remaining eye. Visual fields and dark adaptation were adversely affected in a few cases, but colour vision was normal in all.
CONCLUSION: Bilateral retinoblastoma seems to be associated with superior cognitive capacities. Few children were visually impaired according to WHO criteria. We speculate that children treated during the first months of life may be at risk of adverse cognitive and visual outcomes. The immature brain may be affected by radiation treatment, causing both cognitive and visual deviations.