糖尿病性视网膜血管径改变

Changes of retinal vessel diameters in diabetics

目的 量化糖尿病视网膜动静脉血流与血管横径的改变。方法 糖尿病患者和非糖尿病对照组眼底彩色照相和荧光血管造影检查 ,比较检查结果 ,并统计分析。结果 眼底荧光造影的血管横径显著大于彩照的血流横径 ;糖尿病组的血管横径大于对照组 ;颞侧的血管横径大于鼻侧 ;用彩色照片计算的第 4分支动静脉比值大于用荧光造影结果计算。结论 颞侧分支血管横径和其轴流宽度相对大于鼻侧 ,与颞侧视网膜面积较大 ,颞侧视网膜起主要的感光功能 ,新陈代谢较旺盛 ,需氧量增加 ,血流量增多有关。视网膜血管湍流表现为彩照的血流宽度等于甚至大于荧光造影的血管横径。在视网膜动脉第 4分支可见血流以湍流方式流动 ,表明分支血管血流速度加快 ,或血管阻力增加。荧光造影动静脉期 ,静脉外周血浆层最早呈现荧光 ,说明在微小静脉腔内 ,越靠近管壁流速不是越慢 ,反而是最快。这种血流逆反轴流现象可解释血管口径变小反而血流阻力降低的原因。糖尿病组的静脉分支血管横径大于非糖尿病组的同级血管径 ,与糖尿病视网膜组织缺血 ,高血糖使视网膜血管径自我调节力受损有关。对疑似高血压或动脉粥样硬化 ,特别是伴糖尿病者 ,最好应用荧光造影结果来测量动静脉血管比值 ,避免眼底镜检查方法判定血管动脉硬化的高假阴性率 ,防止漏?

Objective To measure and analyze the changes of retinal vessel and flow diameters.Methods Diabetics and non diabetics were examined with fundus color photo and fundus fluorescein angiography(FFA).The parameters of retinal vessel in photos between two groups were compared and analyzed.Results The diameters of retinal vessel in FFA were longer than those in color photo.Those in diabetics were also longer than those in non diabetics.Those in temple section were longer than those in nasal section.The ratio of artery to vein in fourth branch varied with color photo or FFA.Conclusions The bigger diameter of temple section was related with the larger area and higher metabolism rate of retina of this section.The bigger flow diameters compared to those in vessels indicated that blood flow in fourth branch was turbulent flow,which was due to the increase of blood velocity or resistance Decrease of resistance of blood flow in smaller diameter of retinal vessel was possibly due to the blood velocity of the outer layer that was faster,which reverse the regular laminar flow.Because of ischemia of retina and damage of auto regulation in retinal vessel,the diameters of vessel in diabetics were bigger.The best way to measure the ratio of artery to vein was with FFA,since the higher false negative results calculated from color photo of fundus.