ABSTRACT
Background Influence of weightlessness on visual function has been a hot topic in aerospace medicine field.Electroretinography (ERG) is valuable tool of evaluating visual function.Objective This study aims to observe the influence of head down tilt simulated weightlessness on ERG.MethodHead down tilt for 6° was adopted in 6 healthy volunteers.Flash ERG,including rod response,maxium response,cone response,oscillatory potentials (OPs) and 30 Hz flicker was recorded,and the latency and amplitude from each wave were analyzed before,two days and five days after trial.The record procedure followed the ISCEV standard for full field clinical electroretinography (2008 update).Oral informed consent was obtained from all the subjects prior to the trail.Results No significant differences were detected in the latencies and amplitudes of a,b waves of cone response and 30 Hz flicker among various time points(P＞0.05).The latencies were significantly prolonged in b wave of rod and a,b waves of maxim responses(P＜0.01),but no obvious change was found in amplitudes (P＞0.05).Both the latency and amplitude of all of the wavelets of OPs were considerably among the different time points(P＜0.05-0.01),and the ∑OPs was evidently different among the different time points(P＜0.05).Conclusion Head down tilt simulated weightlessness induce the abnormality of visual function in the early stage.
ABSTRACT
Objective To observe the influence of head-down tilt on visual evoked potential.Methods Six healthy volunteers were exposed to-6? head-down tilt.The visual evoked potential were measured before the test,the second day and the fifth day of the test under different space frequency.Results No significant difference was found in the latency of P100 before and after the test.The amplitude of P100 had significant change under high space frequency.But not the same happened on middle and low space frequency.Conclusion head-down tilt can induce the change of visual evoked potential under high space frequency,which means the weightlessness may influent the visual function.
ABSTRACT
Objective To explore the morbidity rate and risk factors of proliferative diabetic retinopathy (PDR) in type 2 diabetes. Methods The clinical data of patients, with PDR in 2739 consecutive cases of type 2 diabetes diagnosed in this hospital from 1994 to 2001 were analyed retospectively. The diagnosis of diabetic retinopathy (DR) was confirmed by ophthalmoscopy and fundus fluorescein angiography (FFA). Blood pressure, fasting and postprandial blood sugar, glycosylated haemoglobin(HbA1c), total serum cholesterol, triglyceride, creatinine, and albumin excretion rate were measured. Results The morbidity rate of type 2 DR was 27.8%(761/2739), and the morbidity rate of PDR was 4. 2%(114/2 739) occupying 15% of the patients with DR. The duration, fasting blood sugar, glycosylated haemoglobin, blood pressure and albumin excretion rate were much higher than those in the control ( P