Superior intelligence of children blinded from retinoblastoma.

It has been widely discussed amongst teachers of the blind that the children blinded from retino-blastoma are generally of above average intelligence. In an investigation into the intelligence of blind children, undertaken by the writer (1956), the IQ results obtained by this particular group of children suggested an above-average trend. The present investigation was therefore undertaken to study the intelligence of children at blind school whose blindness was due to retinoblastoma. A retinoblastoma is a malignant tumour of the eye, originating from immature retina cells. The incidence has been variously estimated as being from 1 in 21,000 to 1 in 34,000 live births. Boys and girls are usually affected in about equal numbers. Retinoblastoma may occur during fetal life and so be manifest at birth. In approximately 70% of cases the tumours are discovered before the age of 3, and in the majority of the rest before 6. In about 30 % the tumours are bilateral, these being unconnected, independent foci of growth. The affected offspring of retinoblastoma survivors are particularly prone to bilateral tumours. That there is a hereditary factor in retinoblastoma is well recognized. Extensive work on this subject has been done by the Children's Tumour Registry and the Department of Ophthalmology in the