June 2015
Volume 56, Issue 7
ARVO Annual Meeting Abstract  |   June 2015
Light exposure, activity and sleep in children: continuous objective measurement
Author Affiliations & Notes
  • Lisa A Ostrin
    Optometry, University of Houston College of Optometry, Houston, TX
  • Footnotes
    Commercial Relationships Lisa Ostrin, None
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    Support None
Investigative Ophthalmology & Visual Science June 2015, Vol.56, 2947. doi:
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      Lisa A Ostrin; Light exposure, activity and sleep in children: continuous objective measurement. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2947.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose: Ambient light is believed to have an effect on eye growth and myopia development. Increased light leads to the release of dopamine and melanopsin in the retina. These neurotransmitters have wide reaching influences, not only on eye growth but also circadian rhythm entrainment, mood and sleep. Here, a wrist-worn device is used to characterize patterns in ambient illumination, activity and sleep in children.

Methods: As part of a 2-year longitudinal study, subjects aged 5-10 (n=60) were recruited. A complete eye exam with cycloplegic refraction and biometry was performed. Ambient light exposure, activity and sleep were measured over the following 2 week period using an Actiwatch Sepctrum, which was set to average data over 1 minute epochs, 24 hours a day. Data presented here represent a 2 week wear period during a fall school session. Light exposure is analyzed in terms of white light, as well as the red, green and blue spectral composition.

Results: Average spherical equivalent refraction was +0.87±1.42D (range: +7.75 to -2.81D) and axial length was 22.6±0.8 mm (20.85 to 25.6). The average time spent outside for the group as a whole was 77.7±30.8 minutes, representing a daily light dose of 1.12x106 lux minutes, with the lowest component being blue, 1.12 time more red, and 2.38 times more green. Activity in emmetropes was 585±121 counts per minute (cpm), in myopes was 457±95cpm, and in hyperopes was 586±105cpm. Subjects slept on average 561.5±43min, with a sleep efficiency of 86.7±3.8%.

Conclusions: The Actiwatch Spectrum is a novel device to easily and continuously measure and quantify light exposure, including the spectral composition, as well as activity and sleep in children. Continued use of the device over the two year study period may help elucidate the relationship between development and progression of eye growth with ambient light, its spectral composition, and possible influences of activity, sleep and seasonal patterns.


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