Levitt E A
J Pediatr Ophthalmol. 1976 Jul-Aug;13(4):234-7.
Sighted and blind patients with bilateral retinoblastoma were compared with their unaffected siblings on standardized tests of verbal intelligence. IQs of blind subjects were found to be significantly higher than those of their siblings while no such difference was noted between sighted subjects and their controls. It was concluded that the IQ superiority of the blind group is associated with blindness rather than with the disease.
对患有双侧视网膜母细胞瘤的视力正常和失明患者及其未受影响的兄弟姐妹进行了言语智力标准化测试比较。结果发现，失明受试者的智商显著高于其兄弟姐妹，而视力正常的受试者与其对照组之间未发现此类差异。研究得出结论，失明组的智商优势与失明有关，而非与疾病有关。
