dark adaptation .därk- n the phenomena including dilation of the pupil, increase in retinal sensitivity, shift of the region of maximum luminosity toward the blue, and regeneration of rhodopsin by which the eye adapts to conditions of reduced illumination compare LIGHT ADAPTATION
dark-adapt·ed 'därk-ə-.dap-təd adj
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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 rod - the cells of the retina that function best in dim light - and the reflex enlargement of the pupil (see pupillary reflex). Compare light adaptation.
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the adaptation of the eye to vision in the dark or in reduced illumination (night vision), with build-up of rhodopsin in the retinal rods; called also scotopic a.Medical dictionary. 2011.