dark/light adaptation
Dark and light adaptation refer to the increased and decreased
(respectively) visual
sensitivity when you enter the opposite environment (i.e. one walks into
a dark room from
a bright location, or vice versa). We generally adapt to the new
lighting conditions, but in
the meantime our vision is somewhat impaired. The pupil contracts or
dilates in order to
adjust, and the amount of time depends on the situation. Strangely
enough, it takes about
one minute to adapt to a light environment, while it takes ten minutes
for one to adapt to a
dark environment. In fact, it actually takes 30-40 minutes for the
rods to adapt to the
dark, and 10 minutes for the cones. Adapting to the dark takes much
longer than the light, and the reasons for this are as yet uncertain.
