Study On Relation Of Visual Fatigue And Sub-health Based On Pulse Signals

With the increasing popularity of computers, more and more VDT (Visual Display Terminal) jobs appear in people's work and life. In particular, in many industries of the modern industry related to the VDT operations, the accidents occurred related to the fatigue status, such as real-time monitoring, vehicle driving, traffic scheduling, air controlling, and other high-risk operations. Compared with the traditional operation, the obvious symptom of VDT operation is visual fatigue caused by overuse. The main symptoms of visual fatigue status are fatigues,difficulties in concentrating attention on the things, decrease of sensitivity, vigilance, brain excitability and work efficiency. The human brain is running long and too heavily overloaded, and the physiological functions would be reduced or destroyed under long-term state of fatigue, causing various diseases, among which the eye disease is the most obvious. Therefore, the prevention of visual fatigue is the key to prevent the invasion of various diseases.Sub-health state is a physiological state, under which the body has no specific disease but shows the reducing activity and declining adaptability, is the third state between health and disease. About 70% of the population is in sub-health state. Sub-health is difficult to detect and evaluate in the clinical examination because of the unclear pathological symptom. So many medical experts think that the sub-health is becoming the century disease to threaten the health of global human.To search for the objective evaluation basis of visual fatigue and sub-health status and explore the relation between fatigue and sub-health,20 groups pulse image signals of VDT visual fatigue and sub-health are collected respectively by using self-made pulse image sensor. Some features such as pulse amplitude, pulse frequency, pulse width, pulse length, and vascular axis displacement are extracted after preprocessing and analysis image signals. These parameters can reflect information about human body's physiology and pathology.The study results show that the pulses visualization acquisition system can acquire more features that can express pulse space time variation; the pulse feature values of visual fatigue and sub-health have significant differences compare with that of health status, but the feature values of status of visual fatigue are very close to that of sub-health. The results have significance for preventing and evaluating the sub-health status, and exploring the mechanism and relation between sub-health and fatigue.