Continuous Objective Assessment of Near Work

Rachel Williams,Lisa A Ostrin,Edwin J Ostrin,Suyash Bakshi

doi:10.1038/s41598-019-43408-y

Rachel Williams, Lisa A Ostrin + Show 2 more

Open Access

https://doi.org/10.1038/s41598-019-43408-y

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Abstract

Evidence regarding the role of near work in myopia is conflicting. We developed the RangeLife, a device for continuous, objective measurement of working distance. Four devices were built, calibrated, and validated. Then, adult subjects wore the device on weekdays and weekend days, while simultaneously wearing an actigraph device for objective measurements of light exposure and activity. Subjects maintained an activity log and answered a visual activity questionnaire. RangeLife data were downloaded and binned into 0.10 m intervals. Objective diopter hours (dh), a weighted measure of near work, were calculated. Diopter hours for all subjects were significantly higher on weekdays (14.73 ± 4.67 dh) compared to weekends (11.90 ± 4.84 dh, p = 0.05). 94 ± 1.85% of near and intermediate viewing distances were recorded when the subjects were exposed to mesopic and indoor photopic light levels (<1000 lux), and 80.03 ± 2.11% during periods of sedentary physical activity (<320 counts per minute). Subjective reports of time viewing near and intermediate distances significantly overestimated objective measures (p = 0.002). The RangeLife was shown to provide reliable measures of viewing distance, and can be further utilized to understand potential influences of viewing behaviors on refractive error.

Highlights

Evidence regarding the role of near work in myopia is conflicting
The results of this study demonstrate the validity and feasibility of continuous, objective assessment of near and intermediate viewing distances using the RangeLife device
We developed a classification scheme for categorizing near to intermediate distances in 0.1 m bins, and established a method for calculating objective diopter hours

Summary

Introduction

Evidence regarding the role of near work in myopia is conflicting. We developed the RangeLife, a device for continuous, objective measurement of working distance. Subjective reports of time viewing near and intermediate distances significantly overestimated objective measures (p = 0.002). Hours spent reading at a near distance is given more weight than hours spent using a computer at an intermediate distance This metric does not fully describe the complexity of viewing behaviors that may influence eye growth, such as the temporal properties of near viewing. Napper, et al, showed that brief interruptions of form deprivation with normal vision significantly decreased the magnitude of myopia in chicks[34] These findings suggest that reading breaks might be beneficial during prolonged near tasks. The development of a device that provides continuous, objective assessment of viewing distance offers the opportunity to assess such behaviors to understand their influence on myopia onset and progression in humans

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Results

Conclusion