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Author Czeisler, C.A.; Shanahan, T.L.; Klerman, E.B.; Martens, H.; Brotman, D.J.; Emens, J.S.; Klein, T.; Rizzo, J.F. 3rd
Title Suppression of melatonin secretion in some blind patients by exposure to bright light Type Journal Article
Year 1995 Publication The New England Journal of Medicine Abbreviated Journal N Engl J Med
Volume 332 Issue 1 Pages 6-11
Keywords Human Health; Adolescent; Adult; Aged; Blindness/etiology/*physiopathology; Circadian Rhythm; Female; Humans; *Light; Male; Melatonin/blood/*secretion; Middle Aged; Photic Stimulation; Sleep Initiation and Maintenance Disorders/physiopathology; Visual Perception
Abstract BACKGROUND: Complete blindness generally results in the loss of synchronization of circadian rhythms to the 24-hour day and in recurrent insomnia. However, some blind patients maintain circadian entrainment. We undertook this study to determine whether some blind patients' eyes convey sufficient photic information to entrain the hypothalamic circadian pacemaker and suppress melatonin secretion, despite an apparently complete loss of visual function. METHODS: We evaluated the input of light to the circadian pacemaker by testing the ability of bright light to decrease plasma melatonin concentrations in 11 blind patients with no conscious perception of light and in 6 normal subjects. We also evaluated circadian entrainment over time in the blind patients. RESULTS: Plasma melatonin concentrations decreased during exposure to bright light in three sightless patients by an average (+/- SD) of 69 +/- 21 percent and in the normal subjects by an average of 66 +/- 15 percent. When two of these blind patients were tested with their eyes covered during exposure to light, plasma melatonin did not decrease. The three blind patients reported no difficulty sleeping and maintained apparent circadian entrainment to the 24-hour day. Plasma melatonin concentrations did not decrease during exposure to bright light in seven of the remaining blind patients; in the eighth, plasma melatonin was undetectable. These eight patients reported a history of insomnia, and in four the circadian temperature rhythm was not entrained to the 24-hour day. CONCLUSIONS: The visual subsystem that mediates light-induced suppression of melatonin secretion remains functionally intact in some sightless patients. The absence of photic input to the circadian system thus constitutes a distinct form of blindness, associated with periodic insomnia, that afflicts most but not all patients with no conscious perception of light.
Address (up) Department of Medicine, Harvard Medical School, Boston, MA 02115
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0028-4793 ISBN Medium
Area Expedition Conference
Notes PMID:7990870 Approved no
Call Number LoNNe @ kagoburian @ Serial 732
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Author Kloog, I.; Portnov, B.A.; Rennert, H.S.; Haim, A.
Title Does the modern urbanized sleeping habitat pose a breast cancer risk? Type Journal Article
Year 2011 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 28 Issue 1 Pages 76-80
Keywords Human Health; ged; Alcohol Drinking/adverse effects; Breast Neoplasms/*etiology; Case-Control Studies; Circadian Rhythm/*radiation effects; Female; Humans; Light/*adverse effects; Middle Aged; Odds Ratio; Risk Factors; *Sleep; Urbanization
Abstract Due to its disruptive effects on circadian rhythms and sleep deprivation at night, shiftworking is currently recognized as a risk factor for breast cancer (BC). As revealed by the present analysis based on a comparative case-control study of 1679 women, exposure to light-at-night (LAN) in the “sleeping habitat” is significantly associated with BC risk (odds ratio [OR] = 1.220, 95% confidence interval [CI] = 1.118-1.311; p < .001), controlling for education, ethnicity, fertility, and alcohol consumption. The novelty of the present research is that, to the best of the authors' knowledge, it is the first study to have identified an unequivocal positive association between bedroom-light intensity and BC risk. Thus, according to the results of the present study, not only should artificial light exposure in the working environment be considered as a potential risk factor for BC, but also LAN in the “sleeping habitat.”
Address (up) Department of Natural Resources and Environmental Management, Graduate School of Management, University of Haifa, Haifa, Israel
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0742-0528 ISBN Medium
Area Expedition Conference
Notes PMID:21182407 Approved no
Call Number LoNNe @ kagoburian @ Serial 770
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Author Kessel, L.; Siganos, G.; Jorgensen, T.; Larsen, M.
Title Sleep disturbances are related to decreased transmission of blue light to the retina caused by lens yellowing Type Journal Article
Year 2011 Publication Sleep Abbreviated Journal Sleep
Volume 34 Issue 9 Pages 1215-1219
Keywords Adult; Age Factors; Aging/*pathology/physiology; Circadian Rhythm/physiology; Cross-Sectional Studies; Female; Fluorometry; Humans; Lens, Crystalline/*pathology/physiopathology; *Light; Male; Middle Aged; Retina/*physiopathology; Risk Factors; *Scattering, Radiation; Sleep Disorders/*etiology; Circadian rhythm; cataract; melanopsin; sleep; blue light
Abstract STUDY OBJECTIVES: Sleep pattern and circadian rhythms are regulated via the retinohypothalamic tract in response to stimulation of a subset of retinal ganglion cells, predominantly by blue light (450-490 nm). With age, the transmission of blue light to the retina is reduced because of the aging process of the human lens, and this may impair the photoentrainment of circadian rhythm leading to sleep disorders. The aim of the study was to examine the association between lens aging and sleep disorders. DESIGN: Cross-sectional population based study. SETTING: The study was performed at the Research Center for Prevention and Health, Glostrup Hospital, Denmark and at the Department of Ophthalmology, Herlev Hospital, Denmark. PARTICIPANTS: An age- and sex-stratified sample of 970 persons aged 30 to 60 years of age drawn from a sample randomly selected from the background population. INTERVENTIONS: Not applicable. MEASUREMENTS AND RESULTS: Sleep disturbances were evaluated by a combination of questionnaire and the use of prescription sleeping medication. Lens aging (transmission and yellowing) was measured objectively by lens autofluorometry. The risk of sleep disturbances was significantly increased when the transmission of blue light to the retina was low, even after correction for the effect of age and other confounding factors such as smoking habits, diabetes mellitus, gender, and the risk of ischemic heart disease (P < 0.0001). CONCLUSIONS: Filtration of blue light by the aging lens was significantly associated with an increased risk of sleep disturbances. We propose that this is a result of disturbance of photoentrainment of circadian rhythms.
Address (up) Department of Ophthalmology, Glostrup Hospital, University of Copenhagen, Denmark. line.kessel@dadlnet.dk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0161-8105 ISBN Medium
Area Expedition Conference
Notes PMID:21886359; PMCID:PMC3157663 Approved no
Call Number IDA @ john @ Serial 344
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Author Landers, J.A.; Tamblyn, D.; Perriam, D.
Title Effect of a blue-light-blocking intraocular lens on the quality of sleep Type Journal Article
Year 2009 Publication Journal of Cataract and Refractive Surgery Abbreviated Journal J Cataract Refract Surg
Volume 35 Issue 1 Pages 83-88
Keywords Aged; Aged, 80 and over; Circadian Rhythm/physiology; Female; Humans; *Lens Implantation, Intraocular; *Lenses, Intraocular; Light; Male; *Phacoemulsification; Prosthesis Design; Questionnaires; Sleep/*physiology; blue light; sleep
Abstract PURPOSE: To evaluate whether implantation of a blue-light-blocking intraocular lens (IOL) affects sleep quality. SETTING: Repatriation General Hospital, Adelaide, Australia. METHODS: This study comprised patients who had bilateral cataract surgery during the preceding 12 months with implantation of a conventional SI40NB IOL or an AcrySof Natural SN60WF blue-light-blocking IOL. Patients were contacted by telephone at least 6 months after second-eye surgery, and the Pittsburgh Sleep Quality Index (PSQI) questionnaire was administered. Results were compared between groups. RESULTS: Of the 49 patients, 31 received conventional IOLs and 18, blue-light-blocking IOLs. The mean age of the patients was 80 years +/- 8.1 (SD). The median PSQI score was 6 (interquartile range 3 to 8). There were no statistically significant differences in PSQI scores between the 2 IOL groups (P = .65). This remained true after adjustment for sex, age, medication, and time since surgery. CONCLUSION: The blue-light-blocking IOL had no effect on the sleep quality of patients, indicating that these IOLs might serve as an alternative to conventional IOLs without a detrimental effect on circadian rhythm.
Address (up) Department of Ophthalmology, Repatriation General Hospital, Adelaide, Australia. john.landers@bigpond.com
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0886-3350 ISBN Medium
Area Expedition Conference
Notes PMID:19101429 Approved no
Call Number IDA @ john @ Serial 288
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Author Thorn, L.; Hucklebridge, F.; Esgate, A.; Evans, P.; Clow, A.
Title The effect of dawn simulation on the cortisol response to awakening in healthy participants Type Journal Article
Year 2004 Publication Psychoneuroendocrinology Abbreviated Journal Psychoneuroendocrinology
Volume 29 Issue 7 Pages 925-930
Keywords Human Health; Adult; Affect/*physiology/radiation effects; Arousal/*physiology/radiation effects; Circadian Rhythm/*physiology; Female; Humans; Hydrocortisone/analysis/*physiology/radiation effects; *Light; Male; Middle Aged; Reference Values; Saliva/chemistry; Wakefulness/*physiology/radiation effects
Abstract Bright light exposure after awakening has been shown to elevate cortisol levels in healthy participants. The present study examined the effect of dawn simulation (a treatment for seasonal affective disorder) on the cortisol response to awakening and mood. Twelve healthy participants were supplied with a dawn simulator (The Natural Alarm Clock, Outside In, Cambridge Ltd), a bedside light that increases in intensity prior to awakening to approximately 250 lux over 30 mins when an audible alarm sounds. A counterbalanced study was performed on 4 consecutive normal weekdays, two of which were control days (no dawn simulation) and two experimental (dawn simulation). Saliva samples were taken immediately on awakening then at 15, 30 and 45 minutes post awakening on all 4 study-days. Total cortisol production during the first 45 mins after awakening was found to be significantly higher in the experimental condition than in the control condition. Participants also reported greater arousal in the experimental condition and there was a trend for an association between increased arousal and increased cortisol secretory activity under dawn simulation. This study provides supportive evidence for the role of light and the suprachiasmatic nucleus in the awakening cortisol response.
Address (up) Department of Psychology, University of Westminster, 309 Regent Street, London W1R 8AL, UK
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0306-4530 ISBN Medium
Area Expedition Conference
Notes PMID:15177708 Approved no
Call Number LoNNe @ kagoburian @ Serial 824
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