dark adaptation

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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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

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
Farlex Partner Medical Dictionary © Farlex 2012

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.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

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.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

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).
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

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.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
NiONP improved the ERG b-wave amplitude both in dark-adapted and light-adapted status (Figure 4 and 5), which indicated that NiONP have the ability to improve the functions of both rods (Figure 4, dim intensity) and cones (Figure 5, under background illumination).
Contrary to the maximal and effective PSII quantum yield ([F.sub.v]/[F.sub.m] and [DELTA]F/[F.sub.m]' respectively), the quantification of non-photochemical quenching (NPQ) requires parameters measured at different stages of an experiment ([F.sub.m] and [F.sub.m]' maximal fluorescence emitted by a dark-adapted or light-adapted sample).
The B- and D-type cells described in this study correspond with two analogous types of photosensitive cells extracted from the dark-adapted snail retina using tripsin (Shekhter & Grechenko, 2009).
Suppose that the illumination of the dark-adapted leaf is done with a light flash intense enough to close all the reaction centers (a saturating flash) through multiple turnovers of the PSII.
The observed gold particles falling on different domains in light- and dark-adapted retinas were used to test the null hypothesis of no difference in phosducin labelling distributions between the two study groups.
Leaves were dark-adapted for 10 minutes and chlorophyll fluorescence was measured using an Opti-Sciences OS-30 fluorometer.
Give your eyes at least 20 minutes to become accustomed to the dark and don't look at bright lights once your eyes have dark-adapted. Mars will only seem like a small disc so take a break, look at other objects and then go back to Mars.
The ratio of variable to maximum chlorophyll fluorescence ([F.sub.v]/[F.sub.m]) of dark-adapted leaves provides a means for quantifying maximum quantum efficiency.
The dark-adapted eye becomes more sensitive to the effects of light stimulus.
DEEP-SKY OBJECTS ARE BEST SEEN WHEN YOUR EYES ARE FULLY DARK-ADAPTED.
It was easier to manipulate them in room light, and dark-adapted cells had a tendency to stick to the sides of the cuvette at the entrance and exit of the light beam.
But when using dark-adapted eyes, Nilsson noted that different units did not process light as expected -- suggesting an unknown mechanism was responsible.