Named after Henry Parinaud, a French ophthalmologist (1844–1905), but more precisely termed, dorsal midbrain syndrome, this is an inability to move the pupils upwards (leading to double vision), failure of pupils to react to a closely held light and NYSTAGMUS. It is an important physical sign because it must be due to pressure on a particular area of the brain where the most likely cause is a tumour of the PINEAL GLAND.