Dry eye signs and symptoms in night-time workers

PURPOSE: To determine the effect of night-time working on dry eye signs and symptoms. METHODS: A total of 50 healthy subjects completed a dry eye questionnaire and underwent clinical examinations including basic Schirmer's test and tear breakup time (TBUT) test on two consecutive days, before and after the night shift (12-hrs night-shift). RESULTS: All dry eye symptoms were aggravated significantly after the night shift (P < 0.05). Conjunctival redness increased after the night shift (P = 0.001). TBUT reduced significantly after the night-shift (8.06 vs 10.98 s) (P = 0.001). Basic Schirmer's test increased after the night-shift compared to its values before the shift (19.04 vs 17.34 mm) (P = 0.037). CONCLUSION: Our study showed that night-time working can cause tear film instability and exacerbation of dry eye symptoms.