The time taken to adapt to seeing in dim light; an index of vitamin A status as adaptation is slower and less complete in vitamin A deficiency.
A form of adaptation in which the eye adjusts to low levels of illumination.
The reflex changes which enable the eye to continue to see in dim light. For example, the pupil becomes larger and the rods in the retina become more active than the cones.
Adaptation of the visual cycle to changes in light intensity. The process is dependent on adequate vitamin A intake. Failure to adapt to changing light intensity is one of the first symptoms of vitamin A deficiency.
Reflex changes in the eye to allow vision in decreased light (e.g., in dim light after being in normal light); it involves a dilation of the pupil so that more light enters.
The changes that take place in the retina and pupil of the eye enabling vision in very dim light. Dark adaptation involves activation of the rods (the cells of the retina that function best in dim light) and the reflex enlargement of the pupil. Compare light adaptation.
Adjustment of the eyes for vision in dim light.