Notes Kaspar Hauser
 With his revulsion from colour and brightness, his fondness of
dusk and night, his apparently enhanced vision at dusk and night, Mr I.
sounds like Kaspar Hauser, the boy who was confined in a dimly lit cellar
for fifteen years, as Anselm von Feuerbach described him in 1832:
Oliver Sacks: An Anthropologist on Mars
Picador, London 1995, ISBN 0-330-34167-7
The Case of the Color-blind Painter,
p. 34, footnote 29
As to his sight, there existed, in respect to him, no
twilight, no night, no darkness. . . . At night he stepped everywhere
with the greatest confidence; and in dark places, he always
refused a light when it was offered to him.
He often looked with astonishment, or laughed, at persons
who, in dark places, for instance, when entering a house, or
walking on a staircase by night, sought safety in groping their way,
or in laying hold on adjacent objects.
In twilight, he even saw much better than in broad daylight.
Thus, after sunset, he once read the number of a house at a distance
of one hundred and eighty paces, which, in daylight, he
would not have been able to distinguish so far off.
Towards the close of twilight, he once pointed out to
his instructor a gnat that was hanging in a very distant
spider's web. (pp. 83-4)