In a moral sense it is better to face the light than to have it shine
on us indirectly.
Do not make the mistake of supposing that brilliant lights are
harmless except when looked at directly. As a matter of fact
they are even more dangerous when so placed as to shine into the
eyes sidewise or from above, since the eye is less accustomed
to receive bright light from such directions. In other words,
light from such direction falls upon the outer parts of the
surface of the retina, which, being less accustomed to receive
bright light, are the more quickly injured by it. Cases are on
record where persons working in the vicinity of bare lamps so
placed have entirely lost the sight of one or both eyes.--_The
Illuminating Engineer._
(1848)