Aerobic exercise (AE) increases tear secretion and improves tear film stability in patients with dry eye, according to a study published in BMC Ophthalmology.
Researchers conducted a 2-part analysis consisting of 3 groups: dry eye without AE, dry eye with AE, and preclinical dry eye with AE. In part 1, investigators evaluated variations of the Schirmer I test and 6 tear compositions before and after AE (34 eyes in each group). In part 2, they assessed 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). AE was defined as jogging for a period of 30 minutes outdoors. All participants were between the ages of 18-30 years.
Tear volume at 0 minutes after AE increased significantly in the dry eye with AE group compared with baseline (P <.001), and was significantly higher than the dry eye without AE group (P <.001). The dry eye with AE group also experienced a significant reduction in 8-hydroxy-2′ deoxyguanosine after AE compared with baseline (P =.035, P =.045), and was significantly lower than the dry eye without AE group (P =.005, P =.018).
Among the dry eye with AE group, F-NITBUT and A-NITBUT prolonged significantly after AE compared with baseline (P <.001, P =.007, P =.036; P <.001, P =.001, P =.044), and both lasted significantly longer compared with the dry eye without AE group (P <.001, P =.004, P =.004; P <.001, P =.001, P =.005).
At 10 minutes after completion of AE, the number of incomplete blinks and PBR decreased significantly compared with baseline (P <.001; P <.001), while the number of complete blinks in the AE group increased significantly from 3.80±2.83 to 7.90±4.87. At 0 and 30 minutes after completion of AE, visual acuity improved significantly compared with baseline (P =.017, P =.021).
“An intact and regular tear film is an important factor for high-quality retinal images. Dry eye patients with destabilized tear film show higher values of higher-order aberrations. This leads to excessive diopter variation before and after blinking causing visual fluctuation,” according to investigators. “We speculated that the improvement of visual acuity in dry eye patients after AE was related to the change of higher-order aberration caused by the improvement of tear film stability.”
Research limitations include the relatively young age of the study participants compared with the age of patients who traditionally experience dry eye symptoms and failure to conduct adequate follow up.
Sun C, Chen X, Huang Y, et al. Effects of aerobic exercise on tear secretion and tear film stability in dry eye patients. BMC Ophthalmol. Published online January 4, 2022. doi:10.1186/s12886-021-02230-9