어두운 조건에서 디지털기기 사용 시 거리와 휘도에 따른20대 성인의 시기능 변화

Purpose: The effects of the display luminance condition and viewing distance on visual functions during the use of digital devices in the dark were investigated. Methods: Seventeen subjects in their 20s were asked to watch a video on a digital device for 15 min under two different luminance conditions, i.e., low (3.17±1.42 cd/m2) or high (423.7±3.65 cd/m2), at distances of 33 and 50 cm in a scotopic condition (0 lux). To assess changes in visual function before and after use of the digital device, the accommodative amplitude and lag, phorias at near and far distances, AC/A ratio, and stereopsis were measured. Results: Under low luminance at a viewing distance of 33 cm, the change in binocular accommodative amplitude exhibited a statistically significant increase compared with that under high luminance. Under the low-luminance condition, a statistically significant change was observed only at the distance of 33 cm. Accommodative lag did not show a consistent changing pattern based on the luminance or distance. For far phoria, there was a tendency of esophoric shift as the viewing distance decreased, and high luminance tended to induce exophoric shift. Near phoria showed a tendency of esophoric shift under low luminance compared with high luminance at 33 cm. The calculated AC/A ratio showed a larger decrease at 33 cm under high luminance compared with low luminance, with significant change observed only at 33 cm under high luminance.
Regardless of the luminance condition, stereopsis decreased to a greater extent at 33 cm, with a larger decrease observed under high luminance compared with low luminance. Conclusions: This study indicated that in the scotopic condition, using a digital device with a low-luminance display results in smaller changes in visual function and cross-link strength compared with a high-luminance display. Additionally, under the low-luminance condition, stereopsis was less diminished at a distance of 50 cm. Therefore, to minimize changes in visual function and reduce fatigue when using digital devices in the dark, it is recommended to use low-luminance displays and maintain a viewing distance of 50 cm.