An Objective Comparison of Light Intensity and Near-Visual Tasks Between Rural and Urban School Children in China by a Wearable Device Clouclip

Liang, Wen; Qian, Chenggen; Lan, Weizhong; Cao, Yingpin; Li, Xiaoning; Lu, Yiqiu; Lin, Zhenghua; Pan, Lun; Zhu, Haogang; Yang, Zhikuan

doi:10.1167/tvst.8.6.15

Cited by 26 publications

(27 citation statements)

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“…Light exposure profiles may also be better represented by measuring light exposure at eye level, rather than at the wrist, now possible with advances in technology. 84 Reduced subjective sleep quality and quantity, both outputs of the circadian system, have been reported in myopic children. 85,86 These associations have not been consistently demonstrated in studies evaluating sleep and refractive error in adults, either using subjective (questionnaire) or objective (actigraphy) methods of profiling sleep.…”

Section: Discussionmentioning

confidence: 99%

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Elevated Melatonin Levels Found in Young Myopic Adults Are Not Attributable to a Shift in Circadian Phase

Flanagan

Cobice²,

Richardson³

et al. 2020

Invest. Ophthalmol. Vis. Sci.

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To evaluate the relationship between refractive error, circadian phase, and melatonin with consideration of prior light exposure, physical activity, and sleep. METHODS. Healthy young myopic (spherical equivalent refraction [SER] ≤−0.50DS) and emmetropic adults underwent noncycloplegic autorefraction and axial length (AL) measures. Objective measurements of light exposure, physical activity, and sleep were captured across 7 days by wrist-worn Actiwatch-2 devices. Questionnaires assessed sleep quality and chronotype. Hourly evening saliva sampling during a dim-light melatonin onset (DLMO) protocol evaluated circadian phase, and both morning serum and saliva samples were collected. Liquid chromatography/mass spectrometry quantified melatonin. RESULTS. Subjects (n = 51) were aged 21.4 (interquartile range, 20.1−24.0) years. Melatonin was significantly higher in the myopic group at every evening time point and with both morning serum and saliva sampling (P ≤ 0.001 for all). DLMO-derived circadian phase did not differ between groups (P = 0.98). Multiple linear regression analysis demonstrated significant associations between serum melatonin and SER (B =-.34, β =-.42, P = 0.001), moderate activity (B = .009, β = .32, P = 0.01), and mesopic illumination (B =-.007, β =-.29, P = 0.02), F(3, 46) = 7.23, P < 0.001, R 2 = 0.32, R 2 adjusted = .28. Myopes spent significantly more time exposed to "indoor" photopic illumination (3 to ≤1000 lux; P = 0.05), but "indoor" photopic illumination was not associated with SER, AL, or melatonin, and neither sleep, physical activity, nor any other light exposure metric differed significantly between groups (P > 0.05 for all). CONCLUSIONS. While circadian phase is aligned in adult myopes and emmetropes, myopia is associated with both elevated serum and salivary melatonin levels. Prospective studies are required to ascertain whether elevated melatonin levels occur before, during, or after myopia development.

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Section: Discussionmentioning

confidence: 99%

“…Light exposure profiles may also be better represented by measuring light exposure at eye level, rather than at the wrist, now possible with advances in technology. 84 …”

Section: Discussionmentioning

confidence: 99%

Elevated Melatonin Levels Found in Young Myopic Adults Are Not Attributable to a Shift in Circadian Phase

Flanagan

Cobice²,

Richardson³

et al. 2020

Invest. Ophthalmol. Vis. Sci.

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“…Reported range of the second generation Clouclip for distance tracking is 5 to 120 cm, with a 25°beam diameter and a 10°inferiorly directed beam angle, and 1 to 655 336 lux for ambient illumination measurement. 47,48…”

Section: Methodsmentioning

confidence: 99%

Validation of the Clouclip and utility in measuring viewing distance in adults

Bhandari

Ostrin

2020

Ophthalmic Physiologic Optic

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Purpose: To validate the Clouclip, a continuously measuring objective rangefinder, and examine viewing behaviours during various near tasks in non-myopic and myopic adults. Methods: In experiment 1, five Clouclip devices were utilised. An infrared camera was used to visualise and measure infrared beam size and angle. Repeatability for distance tracking was assessed from 5 to 120 cm in 5 cm increments. Accuracy of distance tracking was investigated for paper and iPad targets, spatial integration was calculated, effects of target tilt were determined and light measurements were compared to a lux meter. In experiment 2, viewing behaviour was assessed in 41 subjects (21 non-myopic, 20 myopic) during four 15-min near tasks; (1) passive reading of printed material, (2) active writing on printed material, (3) passive viewing on an electronic device and (4) active engagement on an electronic device. Working distance was compared between tasks and refractive error groups. Results: Clouclip distance tracking showed good repeatability, with a mean difference of 0.34 cm and limits of agreement of AE2.0 cm. Clouclip-measured and actual distances were highly correlated for paper and electronic targets from 5 to 120 cm, with mean differences and limits of agreement of 3.96 AE 13.78 cm and 4.48 AE 8.92 cm, respectively; variability increased for distances >100 cm. Tracking ability increased with larger target sizes; tracking was accurate when the target occupied 1.5%-20.3% of tracking beam area, depending on distance and with target tilt up to AE60 degrees. Clouclip-and lux meter-measured ambient illumination were highly correlated for a wide range of intensities (r = 0.96, p < 0.001), but with greater variability for intensities >20 000 lux. The Clouclip infrared beam was measured to have a diameter of 25.6 AE 2.2°and a downward angle of 10.3 AE 0.5°. For subject testing, viewing distance was significantly closer for active and passive printed tasks (29.5 AE 6.7 cm and 33.2 AE 8.8 cm, respectively) than for active and passive electronic tasks (35.4 AE 8.0 cm and 40.8 AE 10.4 cm, respectively), with no differences between refractive error groups (p = 0.88). Conclusions: The Clouclip performed well in measuring near and intermediate distances and could distinguish between indoor (<1000 lux) and outdoor (>1000 lux) illumination. A closer working distance was observed for printed tasks compared to those on an iPad, with no difference in viewing distance between nonmyopic and myopic adults.

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“…For instance, FitSight comprises a smartwatch with a light sensor and an accompanying smartphone app that logs time spent outdoors and sends feedback to parents and children 306 . Other similar devices have also been launched, such as Clouclip 307 , a cloud-based sensor device that attaches to the sides of spectacles, measures reading distance, ambient illuminance, and distinguishes between indoor and outdoor environments. The device provides real-time feedback to children and generates daily reports to parents that help them to quantify enviro nmental risk factors and monitor myopia-related behaviour.…”

Section: Rasch Analysismentioning

confidence: 99%