Myopia-related behaviors may be monitored and modified by a wearable, spectacle-mounted device that measures viewing distance, light levels, time spent outdoors, and spectral composition, according to a study published in Ophthalmic and Physiological Optics.
Researchers constructed the device prototype using a global positioning system (GPS) sensor, microspectrograph, time-of-flight distance sensor, and an ambient light sensor before performing laboratory testing on a mannequin. The ambient light sensor measured the intensity of light in a working environment and the time-of-flight sensor determined the proximity of nearby objects by measuring the time it took to a laser to reach the object and reflect back toward the device. The microspectrograph determined spectral composition and power for different wavelengths of ambient light, and the GPS used signal strength to determine whether the wearer was indoors or outdoors.
According to the report, reading distance and duration, light level, time spent outdoors and the spectral composition of incident light are risk factors for myopia, and current wearable devices fail to detect spectral composition exposure. An alert indicates when patients have exceeded the predetermined thresholds.
Prototype testing revealed the device’s ability to perform measurements that were in agreement with other measuring devices. The range of indoor light levels were comparable between the prototype and a luxmeter (56-64 lux vs 58-60 lux) and both devices recorded outdoor levels within the 62,000 to 69,000 lux range. Target distance and the distance measured by the prototype were highly correlated (R2= 0.99), and the mean distance measured by the prototype was within 1.5 cm of the actual target distance for distances between 30 and 95 cm. The microspectrograph correctly recorded the peak spectral power of the appropriate color channels when tested with light sources of different wavelengths, the report shows.
“The device will give a new perspective on the potential role of all these risk factors in unison and will help to elucidate the relative roles of daylight intensity, spectral composition and near-work-related factors in myopia development in children in future studies,” according to the researchers. “Such a broad understanding will improve the overall eye health care system.”
Device limitations include bulkiness with respect to weight and size.
Ramamurthy D, Samuel Paulraj AK, Lakshmi T, Rajagopalan T, Lavanya R. Development of smart spectacles to monitor and modify myopia-related health behaviour in children. Ophthalmic Physiol Opt. Published online March 7, 2023. doi:10.1111/opo.13119