The blind subject was studied similarly. He refused
formal ophthalmological examination, but had been
told many years previously that he suffered from
congenital glaucoma. He lost all subjective light
perception at age 40, but was otherwise in good health
and active in volunteer activities involving services
for the visually impaired. The patient was unable to
detect the fixation lights or the background panel
even at its brightest setting of 2500 lux. Prior to the
experiment his hand was passively located 300 upward
and 30° downward. On verbal commands, 'up' and
'down' he was asked to direct his eyes to the imagined
hand locations. ' There was no visible impairment in
his ability to move his eyes in any plane.