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Inferior retinal light exposure is more effective than superior retinal exposure in suppressing melatonin in humansIllumination of different areas of the human retina elicits differences in acute light-induced suppression of melatonin. The aim of this study was to compare changes in plasma melatonin levels when light exposures of equal illuminance and equal photon dose were administered to superior, inferior, and full retinal fields. Nine healthy subjects participated in the study. Plexiglass eye shields were modified to permit selective exposure of the superior and inferior halves of the retinas of each subject. The Humphrey Visual Field Analyzer was used both to confirm intact full visual fields and to quantify exposure of upper and lower visual fields. On study nights, eyes were dilated, and subjects were exposed to patternless white light for 90 min between 0200 and 0330 under five conditions: (1) full retinal exposure at 200 lux, (2) full retinal exposure at 100 lux, (3) inferior retinal exposure at 200 lux, (4) superior retinal exposure at 200 lux, and (5) a dark-exposed control. Plasma melatonin levels were determined by radioimmunoassay. ANOVA demonstrated a significant effect of exposure condition (F = 5.91, p < 0.005). Post hoc Fisher PLSD tests showed significant (p < 0.05) melatonin suppression of both full retinal exposures as well as the inferior retinal exposure; however, superior retinal exposure was significantly less effective in suppressing melatonin. Furthermore, suppression with superior retinal exposure was not significantly different from that of the dark control condition. The results indicate that the inferior retina contributes more to the light-induced suppression of melatonin than the superior retina at the photon dosages tested in this study. Findings suggest a greater sensitivity or denser distribution of photoreceptors in the inferior retina are involved in light detection for the retinohypothalamic tract of humans.
Document ID
20040087867
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Glickman, Gena
(Jefferson Medical College Philadelphia, PA 19107, United States)
Hanifin, John P.
Rollag, Mark D.
Wang, Jenny
Cooper, Howard
Brainard, George C.
Date Acquired
August 21, 2013
Publication Date
February 1, 2003
Publication Information
Publication: Journal of biological rhythms
Volume: 18
Issue: 1
ISSN: 0748-7304
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: R01NS36590
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Space Human Factors
Clinical Trial
Non-NASA Center

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