dark adaptation

(redirected from scotopic adaptation)
Also found in: Dictionary, Thesaurus, Encyclopedia.

adaptation

 [ad″ap-ta´shun]
1. a dynamic, ongoing, life-sustaining process by which living organisms adjust to environmental changes.
2. adjustment of the pupil to light.
biological adaptation the adaptation of living things to environmental factors for the ultimate purpose of survival, reproduction, and an optimal level of functioning.
color adaptation
1. changes in visual perception of color with prolonged stimulation.
2. adjustment of vision to degree of brightness or color tone of illumination.
dark adaptation adaptation of the eye to vision in the dark or in reduced illumination.
light adaptation adaptation of the eye to vision in the sunlight or in bright illumination (photopia), with reduction in the concentration of the photosensitive pigments of the eye.
physiological adaptation the ongoing process by which internal body functions are regulated and adjusted to maintain homeostasis in the internal environment.
psychological adaptation the ongoing process, anchored in the emotions and intellect, by which humans sustain a balance in their mental and emotional states of being and in their interactions with their social and cultural environments.
social adaptation adjustment and adaptation of humans to other individuals and community groups working together for a common purpose.

dark ad·ap·ta·tion

the visual adjustment occurring under reduced illumination in which the retinal sensitivity to light increases.
See also: dark-adapted eye, Purkinje shift.
Synonym(s): scotopic adaptation

dark adaptation

n.
The physical and chemical adjustments of the eye, including dilation of the pupil and increased activity of rods in the retina, that make vision possible in relative darkness.

dark′-a·dapt′ v.
dark′-a·dapt′ed (-ə-dăp′tĭd) adj.

dark ad·ap·ta·tion

(dahrk ad'ap-tā'shŭn)
The visual adjustment occurring under reduced illumination in which the retinal sensitivity to light is increased.
See also: dark-adapted eye
Synonym(s): scotopic adaptation.

dark adaptation

The gradual acquisition of the ability to see in dim light that normally occurs in conditions of poor illumination. Dark adaptation becomes defective (night blindness) in vitamin A deficiency because this vitamin is necessary for the production of retinal VISUAL PURPLE. Poor dark adaptation is also a feature of RETINITIS PIGMENTOSA (tapetoretinal degeneration).

dark adaptation

the increase in light sensitivity of an eye as a result of remaining in the dark, being the time taken for rods to re-form rhodopsin. In total darkness it takes 30 minutes for the rods to adapt and the eye to achieve maximum sensitivity.