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 ?
Such filtering would increase in the dark-adapted state of larval lobster apposition-type eyes when migratory pigments have retracted to the basement membrane, thereby increasing lateral transmission through stationary screening pigments (e.g., Meyer-Rochow, 1975; Goldsmith, 1978).
The spectral sensitivity function for dark-adapted specimens of Abyssorchomene plebs shows a major peak in the blue, with a minor sensitivity peak in the ultraviolet (UV).
The electrophysiologically determined visual spectral sensitivity of dark-adapted specimens of Sergestes similis indicated that the sensitivity maximum was centered at approximately 500 nm in the blue-green region of the spectrum (Fig.
To monitor response latencies of the dark-adapted retina, we measured the delay of the optic nerve response to a brief (35 ms) test flash.
However, these measurements of maximum CFF were made in a completely dark-adapted eye; the eye of F.
Figure 1 plots the amplitudes of ERGs recorded from dark-adapted Tachypleus and Limulus eyes on log scales as a function of log light intensity.
The value at which the response saturates is about 65 ms in a dark-adapted crab.
A much-dimmed torch (shielded with red cellophane) will provide sufficient light, once dark-adapted, to read star charts and make notes and sketches.
For photochemical efficiency, the initial fluorescence (Fo) and maximum fluorescence (Fm) of the dark-adapted leaf, maximum variable fluorescence (Fv), maximum quantum efficiency of PSII (Fv/Fm) from the relationship between maximum variable fluorescence and maximum fluorescence of the dark-adapted leaf were evaluated.
The following photosynthetic parameters were evaluated using Fluorcam7 software (protocol Quenching): [F.sub.0] = minimal fluorescence in dark-adapted state; [F.sub.m] = maximum fluorescence in dark-adapted state; [F.sub.v]/[F.sub.m] = maximum quantum yield; NPQ = non-photochemical
Plastic tarps, canvas, denim, duck cloth, and similar materials may look dense by day, but at night with dark-adapted eyes it's surprising how much light gets through them.