Accuracy and stability of a smart wearable device for quantitative analysis of environmental risks related to myopia

Objective

To evaluate the accuracy and stability of Eye-Monitor, a smart wearable device, in quantifying environmental risks related to myopia.

Methods

A diagnostic test study was conducted.Forty-two subjects aged 18-25 years old were recruited from Shandong University of Traditional Chinese Medicine in December 2021.Forty-two Eye-Monitors were selected from 80 devices using the simple random sampling method.Static and dynamic tests were carried out to compare environmental risks related to myopia.The static tests included measurements under different working distances, different head tilt angles when sitting, and different light intensities.The dynamic tests included measurements under different near-work time, different outdoor activity time, different time watching computers, and different phone viewing time.Eye-Monitor with the largest sum of absolute values of total relative error was selected, Spearman rank correlation analysis was used to analyze the correlation between the set values and Eye-Monitor measurements, and the accuracy of the objectively measured values was evaluated by Bland-Altman consistency analysis.The stability of the objectively measured values from Eye-Monitor was evaluated by the coefficient of variation.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine (No.HEC-KS-2021005KY). Written informed consent was obtained from each subject.

Results

There were significant correlations between the measured values and setting values in the working distance, head tilt angle when sitting, indoor light intensity, total near-work time, average continuous near-work time, outdoor activity time, time watching computers, and time viewing phones (r_s=0.999, 0.998, 0.999, 0.998, 0.976, 0.959, 0.992, 0.997; all at P<0.001), with the 95% limits of agreement (LoA) of-1.23-2.32 cm, -1.49-4.24°, -13.90-26.90 lx, -6.46-0.11 minutes, -4.50-1.20 minutes, -4.01-1.34 minutes, -2.54-1.94 minutes and-2.15-0.45 minutes, respectively.More than 95% of dots were within the clinically acceptable LoA.The coefficients of variation of the measured values ranged from 1.23%-2.99%, 2.39%-8.25%, 0.87%-8.03%, 1.49%-12.52%, 6.63%-13.59%, 0.00%-14.15%, 1.20%-8.33 and 1.49%-12.51%, respectively, showing good stability.Eye-Monitor had good accuracy in measuring outdoor light intensity (95% LoA: -336.50-130.00 lx).

Conclusions

The smart wearable device Eye-Monitor can be used to objectively monitor working distance, head tilt angle when sitting, indoor light intensity, total near-work time, average continuous near-work time, outdoor activity time, time watching computers, and time watching phones, which are with good accuracy and stability.

Myopia; Environmental exposure; Wearable electronic devices; Working distance; Outdoor activity; Accuracy; Stability