Document Detail

Bright light induces choroidal thickening in chickens.
MedLine Citation:
PMID:  24076544     Owner:  NLM     Status:  MEDLINE    
PURPOSE: Bright light is a potent inhibitor of myopia development in animal models. Because development of refractive errors has been linked to changes in choroidal thickness, we have studied in chickens whether bright light may exert its effects on myopia also through changes in choroidal thickness.
METHODS: Three-day-old chickens were exposed to "bright light" (15,000 lux; n = 14) from 10 AM to 4 PM but kept under "normal light" (500 lux) during the remaining time of the light phase for 5 days (total duration of light phase 8 AM to 6 PM). A control group (n = 14) was kept under normal light during the entire light phase. Choroidal thickness was measured in alert, hand-held animals with optical coherence tomography at 10 AM, 4 PM, and 8 PM every day.
RESULTS: Complete data sets were available for 12 chicks in bright light group and nine in normal light group. The striking inter-individual variability in choroidal thickness (coefficient of variance: 23%) made it necessary to normalize changes to the individual baseline thickness of the choroid. During the 6 hours of exposure to bright light, choroidal thickness decreased by -5.2 ± 4.0% (mean ± SEM). By contrast, in the group kept under normal light, choroidal thickness increased by +15.4 ± 4.7% (difference between both groups p = 0.003). After an additional 4 hours, choroidal thickness increased also in the "bright light group" by +17.8 ± 3.5%, while there was little further change (+0.6 ± 4.0%) in the "normal light group" (difference p = 0.004). Finally, the choroid was thicker in the "bright light group" (+7.6 ± 26.0%) than in the "normal light group" (day 5: -18.6 ± 26.9%; difference p = 0.036).
CONCLUSIONS: Bright light stimulates choroidal thickening in chickens, although the response is smaller than with experimentally imposed myopic defocus, and it occurs with some time delay. It nevertheless suggests that choroidal thickening is also involved in myopia inhibition by bright light.
Weizhong Lan; Marita Feldkaemper; Frank Schaeffel
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Optometry and vision science : official publication of the American Academy of Optometry     Volume:  90     ISSN:  1538-9235     ISO Abbreviation:  Optom Vis Sci     Publication Date:  2013 Nov 
Date Detail:
Created Date:  2013-10-24     Completed Date:  2014-03-20     Revised Date:  2014-05-05    
Medline Journal Info:
Nlm Unique ID:  8904931     Medline TA:  Optom Vis Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1199-206     Citation Subset:  IM    
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MeSH Terms
Choroid / pathology*,  radiation effects*
Disease Models, Animal
Myopia / etiology,  prevention & control
Organ Size
Tomography, Optical Coherence
Comment In:
Optom Vis Sci. 2014 Apr;91(4):e94-5   [PMID:  24561964 ]
Optom Vis Sci. 2014 Apr;91(4):e94   [PMID:  24561963 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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