Optometry and Vision Science Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK.
Sport and Exercise Sciences Research Institute, School of Sport, Ulster University, Jordanstown, UK.
Ophthalmic Physiol Opt. 2021 Sep;41(5):1048-1059. doi: 10.1111/opo.12860. Epub 2021 Aug 13.
To compare real-world measures of illumination obtained with the Actiwatch-2 and Clouclip-M2 with 'gold standard' photometry measures and to evaluate the ability of Actiwatch-2 to correctly identify photometer-defined conditions: scotopic (≤0.01 lux), mesopic (0.02-3 lux), indoor photopic (>3-1,000 lux) and outdoor photopic (>1,000 lux); and Clouclip to correctly identify photometer-defined conditions within its operating range (>1 lux). Inter-device reliability of Clouclip for illumination and viewing distance measures was also investigated.
A Hagner-S2 photometer was used as reference. Measures of illumination were obtained from a range of real-world conditions. To investigate inter-device reliability, five Clouclips were simultaneously exposed to varied light conditions and object distances.
Strong correlations existed between illumination measured with the photometer and both Actiwatch-2 (ρ = 0.99, p < 0.0001) and Clouclip (ρ = 0.99, p < 0.0001). However, both devices underestimated illumination compared to the photometer; disparity increased with increasing illumination and was greater for Actiwatch-2 than Clouclip measures. Actiwatch-2 successfully categorised illumination level (scotopic, mesopic, indoor and outdoor photopic) in 71.2% of cases. Clouclip successfully categorised illumination levels as scotopic/mesopic (≤3 lux) and indoor and outdoor photopic in 100% of cases. Mean differences and limits of agreement (LOA) were 430.92 ± 1,828.74 and 79.35 ± 407.33 lux, between the photometer and Actiwatch-2 and photometer and Clouclip, respectively. The Intra-class Correlation Coefficients for illumination and viewing distance measured with five Clouclips were 0.85 and 0.96, respectively.
These data illustrate that different Clouclip devices produce comparable measures of viewing distance and illumination in real-world settings. Both Actiwatch-2 and Clouclip underestimate illumination in the field compared to gold standard photometer measures. The disparity increases at higher levels of illumination and the discrepancy was greater for Actiwatch-2 measures. For researchers interested in categorising light exposure, Clouclip classifies illumination levels >2 lux more accurately than Actiwatch-2 but cannot discriminate between scotopic and low mesopic light.
比较 Actiwatch-2 和 Clouclip-M2 实际测量的光照与“金标准”光度测量值，并评估 Actiwatch-2 正确识别光度计定义条件的能力：暗视（≤0.01 勒克斯）、中间视（0.02-3 勒克斯）、室内明视（>3-1000 勒克斯）和室外明视（>1000 勒克斯）；以及 Clouclip 在其工作范围内（>1 勒克斯）正确识别光度计定义的条件的能力。还研究了 Clouclip 用于光照和观察距离测量的设备间可靠性。
使用 Hagner-S2 光度计作为参考。从一系列实际条件中获得光照测量值。为了研究设备间的可靠性，五个 Clouclips 同时暴露在不同的光照条件和目标距离下。
光度计测量的光照与 Actiwatch-2（ρ=0.99，p<0.0001）和 Clouclip（ρ=0.99，p<0.0001）之间存在很强的相关性。然而，与光度计相比，两种设备都低估了光照；差异随光照增加而增加，且 Actiwatch-2 测量值的差异大于 Clouclip 测量值。Actiwatch-2 在 71.2%的情况下成功分类光照水平（暗视、中间视、室内明视和室外明视）。Clouclip 成功地将光照水平分类为暗视/中间视（≤3 勒克斯）和室内和室外明视，在 100%的情况下都是如此。光度计与 Actiwatch-2 之间和光度计与 Clouclip 之间的平均差异和一致性界限（LOA）分别为 430.92±1828.74 勒克斯和 79.35±407.33 勒克斯。五个 Clouclips 测量的光照和观察距离的组内相关系数分别为 0.85 和 0.96。
这些数据表明，不同的 Clouclip 设备在真实环境中产生可比较的观察距离和光照测量值。与金标准光度计测量值相比，Actiwatch-2 和 Clouclip 在现场都低估了光照。在较高水平的光照下，差异会增加，且 Actiwatch-2 测量值的差异更大。对于有兴趣对光暴露进行分类的研究人员来说，Clouclip 比 Actiwatch-2 更准确地分类>2 勒克斯的光照水平，但不能区分暗视和低中间视光。
