HEALTHY PUPIL CONSTRICTION AND DILATION
Reading on a video screen is more taxing than reading printed text due to screen glare, poor lighting or posture, or viewing at the wrong distance or angle, among other reasons. People on computers tend to blink less than while reading print, drying the eyes and contributing to strain.
In this study, 32 healthy adults with video screen eye fatigue took a placebo or 120 mg of anthocyanin-rich bilberry extract powder per day. After six weeks, compared to placebo, those taking bilberry had smoother constriction and dilation of the pupils, clearer vision, less watery eyes, and less eye fatigue.
Discussing the findings, doctors said one of the symptoms of video-screen eye strain is a decrease in pupil constriction and dilation. “Pupillary constriction increases the depth of focus and contributes to the expansion of the clear vision region,” doctors said, meaning smooth constriction increases the range of distance people can clearly see.
Reference: Functional Foods in Health and Disease; 2021; Vol. 11, No. 3, 116-46