デジタルデバイスユーザーにおける人工涙液の眼表面症状および視覚タスクパフォーマンスへの影響

This prospective, single-arm study investigates the effects of preservative-free artificial tears on ocular symptoms, visual task performance, and tear film stability in visual display terminal (VDT) users. Thirty VDT users with digital eye strain and dryness symptoms were prescribed preservative-free artificial tears four times daily for one month. Ocular Surface Disease Index (OSDI) and Computer-Vision Symptom Scale (CVSS17) questionnaires were collected at four visits (screening, initial, one week and one month). Blink rate and eye fixations during six simple computer tasks and out-loud reading speed were determined before and after computer use. Noninvasive tear film break-up time (NIBUT) and tear meniscus height (TMH) were also recorded. VDT users' symptoms [CVSS17 (35.70 ± 3.72 to 27.27 ± 4.43; P < 0.01); OSDI (19.99 ± 3.20 to 10.52 ± 6.04; P < 0.01)] improved after artificial tear use at final visit. Out-loud reading speed did not significantly change, although a slight improvement in the normalized value was observed after computer use between the initial (0.99 ± 0.13) and final (1.02 ± 0.15; P < 0.01) visits. No significant differences between visits were found in the blink rate, eye fixations, NIBUT or TMH. Preservative-free artificial tears effectively reduce subjective symptoms in VDT users, although this relief does not translate into measurable improvements in visual task performance or tear film metrics.