Light exposure and physical activity in myopic and emmetropic children
Purpose: To objectively assess daily light exposure and physical activity levels in myopic and emmetropic children.
Methods: One hundred and two children (41 myopes and 61 emmetropes) aged 10 to 15 years old had simultaneous objective measures of ambient light exposure and physical activity collected over a 2 week period during school term, using a wrist worn actigraphy device (Actiwatch-2). Measures of visible light illuminance and physical activity were captured every 30 seconds, 24 hours a day over this period. Mean hourly light exposure and physical activity for weekdays and weekends were examined. To ensure that seasonal variations didn’t confound comparisons, the light and activity data of the 41 myopes, was compared with 41 age and gender matched emmetropes who wore the Actiwatch over the same two week period.
Results: Mean light exposure and physical activity for all 101 children with valid data exhibited significant changes with time of day and day of the week (p<0.0001). On average greater daily light exposure occurred on weekends compared to weekdays (p<0.05), and greater physical activity occurred on weekdays compared to weekends (p<0.01). Myopic children (n = 41, mean daily light exposure 915 ± 519 lux) exhibited significantly lower average light exposure compared to 41 age and gender matched emmetropic children (1272 ± 625 lux, p<0.01). The amount of daily time spent in bright light conditions (>1000 lux) was also significantly greater in emmetropes (127 ± 51 minutes) compared to myopes (91 ± 44 minutes, p<0.001). No significant differences were found between the average daily physical activity levels of myopes and emmetropes (p>0.05).
Conclusions: Myopic children exhibit significantly lower daily light exposure, but no significant difference in physical activity compared to emmetropic children. This suggests the important factor involved in documented associations between myopia and outdoor activity is likely exposure to bright outdoor light rather than greater physical activity.
Impact and interest:
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|Item Type:||Journal Article|
|Keywords:||myopia, light exposure, physical activity, outdoor activity, childhood|
|Subjects:||Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Optical Technology (111302)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Optometry and Ophthalmology not elsewhere classified (111399)
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Current > Schools > School of Optometry & Vision Science
|Copyright Owner:||Copyright 2014 American Academy of Optometry|
|Copyright Statement:||This is a non-final version of an article published in final form in Optometry & Vision Science: March 2014 - Volume 91 - Issue 3 - p 330-341, doi: 10.1097/OPX.0000000000000160|
|Deposited On:||27 Feb 2014 23:54|
|Last Modified:||07 Apr 2015 07:35|
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