toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author Ostrin, L.A. url  doi
openurl 
  Title Ocular and systemic melatonin and the influence of light exposure Type Journal Article
  Year 2018 Publication Clinical & Experimental Optometry Abbreviated Journal Clin Exp Optom  
  Volume in press Issue Pages in press  
  Keywords Vision; Review; Human Health  
  Abstract Melatonin is a neurohormone known to modulate a wide range of circadian functions, including sleep. The synthesis and release of melatonin from the pineal gland is heavily influenced by light stimulation of the retina, particularly through the intrinsically photosensitive retinal ganglion cells. Melatonin is also synthesised within the eye, although to a much lesser extent than in the pineal gland. Melatonin acts directly on ocular structures to mediate a variety of diurnal rhythms and physiological processes within the eye. The interactions between melatonin, the eye, and visual function have been the subject of a considerable body of recent research. This review is intended to provide a broad introduction for eye-care practitioners and researchers to the topic of melatonin and the eye. The first half of the review describes the anatomy and physiology of melatonin production: how visual inputs affect the pineal production of melatonin; how melatonin is involved in a variety of diurnal rhythms within the eye, including photoreceptor disc shedding, neuronal sensitivity, and intraocular pressure control; and melatonin production and physiological roles in retina, ciliary body, lens and cornea. The second half of the review describes clinical implications of light/melatonin interactions. These include light exposure and photoreceptor contributions in melatonin suppression, leading to consideration of how blue blockers, cataract, and light therapy might affect sleep and mood in patients. Additionally, the interactions between melatonin, sleep and refractive error development are discussed. A better understanding of environmental factors that affect melatonin and subsequent effects on physiological processes will allow clinicians to develop treatments and recommend modifiable behaviours to improve sleep, increase daytime alertness, and regulate ocular and systemic processes related to melatonin.  
  Address University of Houston College of Optometry, Houston, Texas, USA  
  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 0816-4622 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30074278 Approved no  
  Call Number (up) GFZ @ kyba @ Serial 1986  
Permanent link to this record
 

 
Author Nickla, D.L. url  doi
openurl 
  Title Ocular diurnal rhythms and eye growth regulation: where we are 50 years after Lauber Type Journal Article
  Year 2013 Publication Experimental eye Research Abbreviated Journal Exp Eye Res  
  Volume 114 Issue Pages 25-34  
  Keywords Vision; Human Health; Review  
  Abstract Many ocular processes show diurnal oscillations that optimize retinal function under the different conditions of ambient illumination encountered over the course of the 24 h light/dark cycle. Abolishing the diurnal cues by the use of constant darkness or constant light results in excessive ocular elongation, corneal flattening, and attendant refractive errors. A prevailing hypothesis is that the absence of the Zeitgeber of light and dark alters ocular circadian rhythms in some manner, and results in an inability of the eye to regulate its growth in order to achieve emmetropia, the matching of the front optics to eye length. Another visual manipulation that results in the eye growth system going into a “default” mode of excessive growth is form deprivation, in which a translucent diffuser deprives the eye of visual transients (spatial or temporal) while not significantly reducing light levels; these eyes rapidly elongate and become myopic. It has been hypothesized that form deprivation might constitute a type of “constant condition” whereby the absence of visual transients drives the eye into a similar default mode as that in response to constant light or dark. Interest in the potential influence of light cycles and ambient lighting in human myopia development has been spurred by a recent study showing a positive association between the amount of time that children spent outdoors and a reduced prevalence of myopia. The growing eyes of chickens and monkeys show a diurnal rhythm in axial length: Eyes elongate more during the day than during the night. There is also a rhythm in choroidal thickness that is in approximate anti-phase to the rhythm in eye length. The phases are altered in eyes growing too fast, in response to form deprivation or negative lenses, or too slowly, in response to myopic defocus, suggesting an influence of phase on the emmetropization system. Other potential rhythmic influences include dopamine and melatonin, which form a reciprocal feedback loop, and signal “day” and “night” respectively. Retinal dopamine is reduced during the day in form deprived myopic eyes, and dopamine D2 agonists inhibit ocular growth in animal models. Rhythms in intraocular pressure as well, may influence eye growth, perhaps as a mechanical stimulus triggering changes in scleral extracellular matrix synthesis. Finally, evidence shows varying influences of environmental lighting parameters on the emmetropization system, such as high intensity light being protective against myopia in chickens. This review will cover the evidence for the possible influence of these various factors on ocular growth. The recognition that ocular rhythms may play a role in emmetropization is a first step toward understanding how they may be manipulated in treatment therapies to prevent myopia in humans.  
  Address New England College of Optometry, Department of Biosciences, 424 Beacon Street, Boston, MA 02115, USA. nicklad@neco.edu  
  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 0014-4835 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23298452; PMCID:PMC3742730 Approved no  
  Call Number (up) GFZ @ kyba @ Serial 1987  
Permanent link to this record
 

 
Author Mard, J.; Di Baldassarre, G.; Mazzoleni, M. url  doi
openurl 
  Title Nighttime light data reveal how flood protection shapes human proximity to rivers Type Journal Article
  Year 2018 Publication Science Advances Abbreviated Journal Sci Adv  
  Volume 4 Issue 8 Pages eaar5779  
  Keywords Remote Sensing  
  Abstract To understand the spatiotemporal changes of flood risk, we need to determine the way in which humans adapt and respond to flood events. One adaptation option consists of resettling away from flood-prone areas to prevent or reduce future losses. We use satellite nighttime light data to discern the relationship between long-term changes in human proximity to rivers and the occurrence of catastrophic flood events. Moreover, we explore how these relationships are influenced by different levels of structural flood protection. We found that societies with low protection levels tend to resettle further away from the river after damaging flood events. Conversely, societies with high protection levels show no significant changes in human proximity to rivers. Instead, such societies continue to rely heavily on structural measures, reinforcing flood protection and quickly resettling in flood-prone areas after a flooding event. Our work reveals interesting aspects of human adaptation to flood risk and offers key insights for comparing different risk reduction strategies. In addition, this study provides a framework that can be used to further investigate human response to floods, which is relevant as urbanization of floodplains continues and puts more people and economic assets at risk.  
  Address IHE Delft Institute for Water Education, 2611 AX Delft, Netherlands  
  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 2375-2548 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30140738; PMCID:PMC6105301 Approved no  
  Call Number (up) GFZ @ kyba @ Serial 1989  
Permanent link to this record
 

 
Author Wilson IV, J.; Reid, K.J.; Braun, R.I.; Abbott, S.M.; Zee, P.C. url  doi
openurl 
  Title Habitual Light Exposure Relative to Circadian Timing in Delayed Sleep-Wake Phase Disorder Type Journal Article
  Year 2018 Publication Sleep Abbreviated Journal  
  Volume in press Issue Pages  
  Keywords Human Health  
  Abstract Study Objectives

To compare melatonin timing, a well validated marker for endogenous circadian phase, and habitual light exposure patterns in adults with delayed sleep-wake phase disorder (DSWPD) and intermediate chronotype controls.

Methods

12 individuals with DSWPD (5 females, mean age 31.1) and 12 age matched controls (6 females, mean age 33.6) underwent a minimum of seven days of light and activity monitoring followed by an inpatient hospital stay, where blood was taken to assess melatonin timing (calculated as dim light melatonin onset – DLMO). Habitual light exposure patterns were then compared to a human phase response curve (PRC) to light.

Results

Relative to clock time, individuals with DSWPD had a later light exposure pattern compared to controls, but their light exposure pattern was earlier relative to DLMO. According to the human phase response curve (PRC) to light, individuals with DSWPD had less daily advancing light exposure compared to controls. The primary difference was seen in the late portion of the advancing window, in which individuals with DSWPD were exposed to fewer pulses of light of equivalent duration and intensity compared to controls.

Conclusions

Diminished advancing light exposure may play a role in the development and perpetuation of delayed sleep-wake timing in individuals with DSWPD. Enhancing light exposure during the later portion of the advancing window represents an innovative and complementary strategy that has the potential to improve the effectiveness of bright light therapy in DSWPD.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language 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 Approved no  
  Call Number (up) GFZ @ kyba @ Serial 1990  
Permanent link to this record
 

 
Author Suh, Y.-W.; Na, K.-H.; Ahn, S.-E.; Oh, J. url  doi
openurl 
  Title Effect of Ambient Light Exposure on Ocular Fatigue during Sleep Type Journal Article
  Year 2018 Publication Journal of Korean Medical Science Abbreviated Journal J Korean Med Sci  
  Volume 33 Issue 38 Pages  
  Keywords Human Health  
  Abstract Background

To investigate the influence of nocturnal ambient light on visual function and ocular fatigue.

Methods

Sixty healthy subjects (30 males and 30 females) aged 19 through 29 years with no history of ocular disease were recruited. All subjects spent 3 consecutive nights in the sleep laboratory. During the first and second nights, the subjects were not exposed to light during sleep, but during the third night, they were exposed to ambient light, measuring 5 or 10 lux at the eye level, which was randomly allocated with 30 subjects each. The visual function and ocular fatigue were assessed at 7 a.m. on the 3rd and 4th mornings, using best-corrected visual acuity, refractive error, conjunctival hyperemia, tear break-up time, maximal blinking interval, ocular surface temperature, and subjective symptoms reported on a questionnaire.

Results

Three male and three female subjects failed to complete the study (4 in the 5 lux; 2 from the 10 lux). For the entire 54 subjects, tear break-up time and maximal blinking interval decreased (P = 0.015; 0.010, respectively), and nasal and temporal conjunctival hyperemia increased significantly after sleep under any ambient light (P < 0.001; 0.021, respectively). Eye tiredness and soreness also increased (P = 0.004; 0.024, respectively). After sleep under 5 lux light, only nasal conjunctival hyperemia increased significantly (P = 0.008). After sleep under 10 lux light, nasal and temporal conjunctival hyperemia, eye tiredness, soreness, difficulty in focusing, and ocular discomfort increased significantly (P < 0.05).

Conclusion

Nocturnal ambient light exposure increases ocular fatigue. Avoiding ambient light during sleep could be recommended to prevent ocular fatigue.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1011-8934 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (up) GFZ @ kyba @ Serial 1991  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records: