不同倾斜体位下脉络膜血液循环变化的差异研究OA

Objective To investigate the differences in choroidal blood circulation under various tilted positions and analyze the effect of postural changes on subfoveal choroidal thickness(SFCT)and choroidal vascularity index(CVI).Methods Twenty-one healthy subjects(39 eyes)were recruited.Using swept-source optical coherence tomography angi-ography(SS-OCTA),SFCT and CVI were measured at the following time points:baseline sitting position,15° head-up tilt,supine position,15° head-down tilt,and after returning to the baseline position.Repeated-measures analysis of vari-ance(ANOVA)was used to compare parameter changes across different positions and time points.Results Postural changes significantly affected SFCT and CVI.At 15° head-down tilt,SFCT and CVI increased by 15.5％and 16.8％,re-spectively,within 1 minute,peaking at 10 minutes(20.0％increase in SFCT and 19.4％increase in CVI).All parame-ters returned to the baseline level 30 minutes after returning to the baseline position(P＞0.05).ANOVA showed signifi-cant effects for position,time,and their interaction(P＜0.001).Conclusion Postural changes reversibly alter choroidal hemodynamics.The head-down position significantly increases SFCT and CVI,which may be related to gravity-induced venous pressure changes and vascular autoregulation.