Can urban forests alleviate eye strain? Evidence from eye-tracking metrics

• Short-term exposure to urban forests aids recovery from eye strain. • Open green space and blue spaces showed the strongest restorative effects • Indoor environments failed to relieve and sometimes worsened eye strain. • Pupil size change was the most sensitive indicator of ocular recovery. With the surge in digital screen use, eye strain has become a growing public health concern. While urban forests are known to support psychological and physiological restoration, their capacity to alleviate eye strain remains underexplored. This study investigates whether short-term exposure to different types of urban forests can facilitate ocular recovery from screen-induced eye strain, using objective eye-tracking metrics. A total of 30 participants were fitted with wearable eye-tracking glasses and watched a 20-minute high-intensity video to induce eye strain before spending 10 minutes in a designated environment (open green space, semi-open green space, enclosed green space, green space with large water area, green space with small water area, and an indoor control). Eye metrics including blink rate, pupil size, fixation count/duration, and saccade count/duration were recorded at baseline, post-stress, and post-recovery. Significant recovery was observed in participants exposed to open green spaces and water-area settings, with reductions in pupil size and blink rate (p < 0.01). In contrast, the indoor environment failed to improve and even exacerbated eye strain. Among all indicators, pupil size change emerged as the strongest correlate of composite recovery. Urban blue-green spaces, especially those that are open and feature water elements, can effectively promote ocular recovery from acute eye strain. These findings underscore the value of incorporating open and water-rich natural elements into urban forestry design and management strategies that promote public well-being.