Effects of aerobic exercise on tear secretion and tear film stability in dry eye patients

Background To study the effects of aerobic exercise (AE) on tear secretion and tear film stability in dry eye patients. Methods This study consisted of two parts, each part included 3 groups, namely dry eye without AE group, dry eye with AE group and pre-clinical dry eye with AE group. In part 1, we studied the variations of Schirmer I test and six tear compositions before and after AE (34 eyes in each group). In part 2, we studied the variations of tear meniscus height, first and average non-invasive tear breakup time (F-NITBUT and A-NITBUT), lipid layer thickness, number of incomplete and complete blinks, partial blink rate (PBR) and visual acuity before and after AE (30 eyes in each group). Results In dry eye with AE group, Schirmer I test at 0 min after AE increased significantly compared to baseline ( P < 0.001), the oxidative stress marker 8-hydroxy-2′-deoxyguanosine after AE decreased significantly compared to baseline ( P = 0.035, P = 0.045), F-NITBUT and A-NITBUT after AE prolonged significantly compared to baseline ( P < 0.001, P = 0.007, P = 0.036; P < 0.001, P = 0.001, P = 0.044), number of incomplete blinks and PBR at 10 min after AE decreased significantly compared to baseline ( P < 0.001; P < 0.001) while number of complete blinks increased significantly ( P < 0.001). Besides, significant differences were also found between dry eye with AE group and dry eye without AE group at all above corresponding time point ( P < 0.05). Conclusion AE promotes tear secretion and improves tear film stability in dry eye patients. AE may be a potential treatment for dry eye. Trial registration Chinese Clinical Trial Registry, ChiCTR2000038673 . Registered 27 September 2020,