Visual Resolution in Humans Fluctuates Over the 24h Period*

Tassi, Patricia; Pellerin, Nicolas; Moessinger, Michèle; Hoeft, Alain; Muzet, Alain

doi:10.1081/cbi-100101042

Cited by 19 publications

(12 citation statements)

References 11 publications

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“…Diurnal visual changes occur with maximal visual resolution and detection before midday and a minimum after midnight (Tassi et al. ,b). In a study on mice, Balkema et al.…”

Section: Discussionmentioning

confidence: 99%

Contrast sensitivity and the effect of 60‐hour sleep deprivation

Koefoed

Assmus

Gould

et al. 2014

Acta Ophthalmologica

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ABSTRACT.Purpose: The study aimed to evaluate the possible influence of prolonged sleep deprivation on achromatic and chromatic (red-green and blue-yellow) contrast sensitivity (CS). Methods: During 60-hr sleep deprivation, CS was measured in 11 naval officers every sixth hour using videographic (Vigra-C) sine-wave-generated stimuli. Results: When comparing the CS measurements obtained in the first and last 24 hr of the study, no statistically significant mean changes of achromatic CS (2.0, 5.9 and 11.8 cpd) or yellow-blue CS (0.6, 2.0 and 4.7 cpd) were found, while a significantly increased mean red-green CS at 2.0 and 4.7 cpd was recorded in the last 24 hr (p = 0.003 in both). The variance of achromatic and chromatic CS measurements in the group did not differ significantly in the first and last 24 hr test periods. Conclusions: Prolonged sleep deprivation does apparently not cause clinically or occupationally significant changes of contrast sensitivity in otherwise healthy subjects with normal visual acuity.

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“…Diurnal visual changes occur with maximal visual resolution and detection before midday and a minimum after midnight (Tassi et al. ,b). In a study on mice, Balkema et al.…”

Section: Discussionmentioning

confidence: 99%

Contrast sensitivity and the effect of 60‐hour sleep deprivation

Koefoed

Assmus

Gould

et al. 2014

Acta Ophthalmologica

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“…The circadian release of melatonin in the eye is responsible for the rhythmic adaptation of phototransduction, for the recycling of biochemical components in the retina, and for other aspects of the retinal physiology. Other rhythmic events in the eye such as visual resolution (Tassi et al 2000), ERG, intraocular pressure (Nickla et al 1998), cats: Sole et al (2007, choroid thickening, and eye growth might be or are also under circadian control.…”

Section: Retinal Clocks In the Eyementioning

confidence: 97%

How Light Resets Circadian Clocks

2014

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The daily revolutions of the earth around its axis are responsible for day and night and its annual orbit around the sun for the seasons with their fluctuations in day length. Most organisms have adapted to these diurnal and annual cycles. The strategies and mechanisms used are quite delicate and complicated.It came as a surprise that photosynthesis and many other processes are, however, additionally controlled by internal clocks. Thus, photosynthesis fluctuates not only during the daily light-dark cycle (=LD; see the List of Abbreviations and http://www.circadian.org/dictionary.html) but also when the plants are kept under LL and constant temperature (Hennessey and Field 1991). However, the period length (period for short) of this rhythmic event then deviates from exactly 24 h and is therefore called circadian (from Latin circa, about, and dies, day). If in the absence of LD and temperature cycles other 24 h time cues (also called zeitgeber, German for time giver) would control the rhythm, it should show an exact 24 h rhythm. This is not the case, demonstrating the endogenous nature of a clock that is locked to light signals (see Fig. 18.1). Spectrum of RhythmsEndogenous rhythms of organisms are not only tuned to the daily cycle of 24 h. The range of rhythms found in organisms covers ultradian (with periods of several hours to very short ones), circadian, and annual (with periods of about a year) rhythms. Other rhythms such as tidal, 14-day, and monthly ones cope with influences of the moon on the earth, mainly on the water movements of the oceans, and they are therefore found in organisms at the coasts and in the sea. Annual rhythms interact with the day-length changes during the year (see below). There are furthermore rhythms with periods covering several years. The following discussion of a "biological clock" is restricted to circadian rhythms. Even they are often not just composed of one clock type but form a "circadian system" consisting of two or more clocks with different prop- Function of Circadian ClocksThe term "clock" usually implies a time-measuring device or function. For instance, the day length (or night length) can be determined by an organism. Since day length is a function of the time of the year (long days in summer, short days in winter), it can be used to time certain events such as flowering or tuber formation of a plant or breeding of birds and mammals during the most appropriate season. These processes are denoted photoperiodism (see Chap. 19).However, a clock can also be used to set a certain temporal order. For instance, the circadian control of our sleepwake cycle ensures that we rise in the morning and fall asleep in the evening at a preferred time. Food intake and digestion are likewise controlled by this clock and gated to certain times of the day (Silver et al. 2011;Duguay and Cermakian 2009;Forsgren 1935). The circadian clock will time these events also under constant conditions. Furthermore, circadian clocks can serve as alarm clocks.

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“…12 Despite these slight changes, the visual system is essentially "ready to go" at any time of the day or night. In contrast, the response of the circadian system will change in the magnitude and in the direction of response depending on the timing of light exposure.…”

Section: Timingmentioning

confidence: 99%

Non-visual effects of light: implications for design

Figueiro

2010

SPIE Proceedings

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Light is not just for vision anymore! Illumination design should consider the needs of the visual and non-visual systems. Discussed are the lighting characteristics impacting these systems and the implications for designing light for architecture.Circadian system, circadian light, spectrum, core body temperature, suprachiasmatic nuclei THE CIRCADIAN SYSTEMLight entering the human eye is transmitted to several other parts in the brain, not just those associated with vision. The world rotates around its axis and, as a result, all creatures on earth experience 24-hour cycles of light and dark 1 . Living organisms have adapted to this cycle by developing biological rhythms that repeat at approximately 24 hour intervals, called circadian rhythms (Latin: circa, about; dies, day).The circadian timing system is composed of three elements: the pacemaker, the input pathways and the output pathways. Circadian rhythms are generated by an internal master clock and are constantly aligned with the environment by zeitgebers (time givers), which are external to the body. The suprachiasmatic nuclei (SCN), known to be the master clock in humans, have an average natural period slightly greater than 24 hours. Environmental cues can reset and synchronize the SCN daily, ensuring that humans' behavioral and physiological rhythms are in synchrony with the daily rhythms found within their environment. Although the circadian system shares receptors and neurons in the retina with the visual system, the retinal ganglion cells exiting the eye for the visual centers are different than those exiting the eye for the circadian system. In 2002, the intrinsically photosensitive retinal ganglion cell (ipRGCs), a novel photoreceptor type in the retina was discovered. 2 The ipRGCs are central to an important "non-visual" response to light by the retina, most notably the regulation of circadian rhythms. It is now well accepted that all three photoreceptors in the retina (rods, cones and ipRGCs) participate in how the retina converts light signal into neural signal for the circadian system.Output pathways include overt rhythms of hormone production and behavior. The most commonly measured output rhythms include hormone production, core body temperature, sleep/wake cycles, and rest/activity rhythms. Melatonin is a hormone produced by the pineal gland at night and under conditions of darkness. Because melatonin production is associated with nighttime, it is called the hormone of darkness. Melatonin gives the body time cues, and it is used as a marker of the circadian clock. Melatonin can be measured in plasma, saliva or urine. Sufficient light at night will acutely cease melatonin production and, depending on the timing of exposure, light can phase shift the timing of melatonin production. Core body temperature is also used as a marker of the circadian clock. It reaches a peak late in the afternoon/early evening and a trough late at night/early in the morning. Core body temperature has an inverse relationship with melatonin. The sleep/wake cycle and rest/...

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Visual Resolution in Humans Fluctuates Over the 24h Period*

Cited by 19 publications

References 11 publications

Contrast sensitivity and the effect of 60‐hour sleep deprivation

Contrast sensitivity and the effect of 60‐hour sleep deprivation

How Light Resets Circadian Clocks

Non-visual effects of light: implications for design

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