Accuracy and stability of ClouclipTM, a novel device to record myopic environmental risks

Objective To evaluate the accuracy and stability of the novel device ClouclipTM (Glasson Technology Co., Ltd, Hangzhou, China) designed to record myopic environmental risks. Methods This experimental study consisted of static and dynamic evaluations. In the static evaluation, 15 devices were randomly selected to measure working distances and ambient illuminance and ultraviolet radiation. The device with the greatest measurement error was chosen to represent the accuracy, while the variance of the measurement error among all devices was utilized to assess the stability. In the dynamic evaluation, 30 volunteers were enrolled to wear the devices for two days. They were requested to report the environmental features dynamically via social media (Wechat), including the time of doing or not doing near-work, outdoor or indoor activities, and wearing or not wearing of the device. The data reported by the subjects were compared with the data detected by ClouclipTM to further evaluate the accuracy. Pearson and Bland-Altman analysis were used to assess the accuracy of the ClouclipTM. Results For the static evaluation: there was significant correlation between the measured and actual values both in distance and illuminance (r=0.998, P<0.001 and r=0.999, P<0.001, respectively). The 95% limit of agreement in working distance and illuminance was 0.18-3.10 cm and 1.02-1.35 lx, respectively. The relative errors for working distance and illuminance were 2.4%-6.5% and 8.9%-20.0%, respectively. The coefficient of variance among all samples was 2.3%-4.3% for working distance and 0.4%-5.6% for illuminance. The rate of correct ultraviolet radiation detection was 100% for all samples. For the dynamic evaluation, the rate of correctly identifying near or far work, indoor or outdoor environment and the wearing or not wearing status was 94.6%, 96.5% and 96.0%, respectively. Conclusion ClouclipTM was able to not only record myopic environmental risks with satisfactory accuracy and stability, but it was also able to determine the temporal pattern for these risk factors. It therefore provides a valuable tool to investigate the role of environmental factors in myopia pathogenesis. Key words: Myopia; Smart device; Accuracy; Stability; Temporal pattern