Introduction: The purpose of this study was to investigate the dysfunction of autonomic control that may be a contributing factor in normal tension glaucoma (NTG) by showing the short-term heart rate variability in NTG patients.
Materials and methods: Newly diagnosed NTG patients and an age-matched normal control group were enrolled in this prospective study. Blood pressure was obtained and the electrocardiogram was monitored for 5 minutes after 30-minute rest in a supine position. Electrocardiographic signals were transferred to a heart rate analyzer. The time and frequency domain parameters of heart rate variability were analyzed between two groups.
Result: In all, 77 NTG patients and 30 healthy controls were included in the study. There were no significant differences between NTG and controls with respect to age, sex, and a hypertensive history, heart rate, systolic pressure, and diastolic pressure. NTG patients showed a significant reduction in the standard deviation of the mean of qualified normal-to-normal intervals in comparison with controls (27.64+/-10.90 vs. 36.22+/-10.21, P=0.041). Low-frequency values in NTG patients were statistically lower than in healthy controls (P=0.001) and the low-frequency/high-frequency ratio was significantly higher in the NTG group (P=0.000).
Discussion: Our study results showed that the dysfunction of an autonomic control is associated with NTG patients.