June 2021
Volume 62, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2021
Objectively Measured Near Work and Light Exposure in Adults
Author Affiliations & Notes
  • Khob Raj Bhandari
    Optometry, University of Houston College of Optometry, Houston, Texas, United States
  • Hanieh Mirhajianmoghadam
    Optometry, University of Houston College of Optometry, Houston, Texas, United States
  • Lisa A Ostrin
    Optometry, University of Houston College of Optometry, Houston, Texas, United States
  • Footnotes
    Commercial Relationships   Khob Bhandari, None; Hanieh Mirhajianmoghadam, None; Lisa Ostrin, None
  • Footnotes
    Support  NIH P30 EY007551
Investigative Ophthalmology & Visual Science June 2021, Vol.62, 2328. doi:
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      Khob Raj Bhandari, Hanieh Mirhajianmoghadam, Lisa A Ostrin; Objectively Measured Near Work and Light Exposure in Adults. Invest. Ophthalmol. Vis. Sci. 2021;62(8):2328.

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

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Abstract

Purpose : Evidence supporting a role for near work in myopia prevalence and progression is conflicting, likely due to the subjective nature in which behaviors are traditionally quantified. Additionally, potential mechanisms have not been elucidated. Animal studies suggest that temporal patterns of myopiagenic stimuli may be significant. Continuous objective measurement of viewing behavior and light exposure may help to better understand contributing factors. Here, a novel sensor, the Clouclip, is further validated in adults.

Methods : Five adults wore a spectacle-mounted Clouclip during waking hours and wrist-worn Actiwatch Spectrum continuously for 7 days. Working distance and illuminance were recorded by the Clouclip every 5 seconds (s) and 2 minutes (min), respectively. Activity and illuminance were recorded by the Actiwatch every 1 min. Subjects maintained a log of activities. Data were analyzed in MATLAB. Near work was defined as viewing distances of 10 to <60 cm, and intermediate work 60 to <100 cm. Near work episodes were defined as >1 min near viewing with no interruption >20 s. Continuous near work was defined as 30 min with no interruptions >60 s. Clouclip- and Actiwatch-measured illuminances were compared, and shifts from indoors to outdoors were quantified.

Results : Clouclip wear time was 14.4±0.6 hours (h) per day. Activities noted in subject logs correlated well to Clouclip-measured distance and illuminance. Mean daily duration of near work was 5.0±2.8 h, and intermediate work was 2.1±1.5 h. Mean daily number of near work episodes was 57.1±31.7 with duration of 4.6±1.2 min each and distance of 33.0±4.2 cm. Mean daily number of continuous near work episodes was 1.7±1.2. Clouclip-measured mean daily light exposure (281±210 lux) was not significantly different than Actiwatch-measured light exposure (125.1±119.8 lux, P=.09). Mean daily wake time spent in illuminance <30 lux, 30 to <1000 lux, >1000 lux, >2000, and >3000 lux were 6.1±2.2 h, 6.6±2.1 h, 0.8±0.8 h, 0.5±0.6 h, and 0.4±0.5 h respectively. The number of shifts between indoors and outdoors was 4.9 ± 4.5 (range: 0-15).

Conclusions : The Clouclip provided continuous, objective data for viewing distance and illuminance that correlated well with subject logs and with the Actiwatch, a widely used light sensor. These findings suggest that the Clouclip will be a valuable tool for quantifying behaviors that have been linked to myopia.

This is a 2021 ARVO Annual Meeting abstract.

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