方法：收集28例47眼DR患者纳入研究组(DR组)，依据DR国际临床分期标准将DR患眼分为两组，其中非增殖组(NPDR组)19例30眼和增殖组(PDR组)11例17眼。取年龄相匹配的27例46眼健康眼作为对照组。所有入选受试者均应用OCTA对黄斑区视网膜行3mm×3mm范围模式扫描，获得4个层面黄斑血流密度图，同时测量3个层面黄斑血流密度，包括表层视网膜层、深层视网膜层和脉络膜毛细血管层。

结果：DR组表层视网膜、深层视网膜及脉络膜层毛细血管层黄斑血流密度分别为0.4963±0.0840、0.4798±0.0801、0.5290±0.0528； 其中NPDR组分别为0.5064±0.0843、0.4983±0.0766、0.5345±0.0529，而PDR组分别为0.4786±0.0830、0.4473±0.0778、0.5192±0.0526； 正常对照组分别为0.5919±0.0704、0.6301±0.0527、0.5691±0.0169。对照组分别和NPDR组、PDR组、DR组表层视网膜、深层视网膜、脉络膜毛细血管层的黄斑血流密度比较，差异有显著统计学差异(P<0.001)。NPDR组和PDR组之间黄斑血流密度在深层视网膜比较，差异有统计学意义(P=0.029)，但在表层视网膜、脉络膜毛细血管层比较，差异无统计学意义(P=0.236、0.268)。

结论：DR患者黄斑血流密度在表层视网膜、深层视网膜和脉络膜毛细血管层均较正常对照组下降，提示黄斑区视网膜及脉络膜均存在缺血现象。OCTA可以量化黄斑血流变化的情况，为早期监测糖尿病的进展、发现DR提供有效手段。

METHODS: Totally 47 eyes(28 patients)with diabetic retinopathy(DR)were enrolled in the DR group. According to the international clinical grading criteria of diabetic retinopathy, 30 eyes(19 patients)with non-proliferative diabetic retinopathy were classified as the NPDR group, and 17 eyes(11 patients)with proliferative diabetic retinopathy were classified as PDR group. A total of 46(27 subjects)healthy eyes with matched age were enrolled in the control group. All the subjects underwent the 3mm×3mm scanning of macular retina by optical coherence tomography angiography(OCTA), obtaining 4 levels of macular blood flow density map. The macular blood flow density at 3 levels, including superficial retinal layer, deep retinal layer and choroidal capillaries layer, were measured.

RESULTS: The macular blood flow density of superfical retinal layer, deep retinal layer and choroidal capillaries layer in DR group were 0.4963±0.0840, 0.4798±0.0801 and 0.5290±0.0528, respectively. Among them, the blood flow density of each layer were 0.5064±0.0843,0.4983±0.0766,0.5345±0.0529, respectively, for the NPDR group, and were 0.4786±0.0830, 0.4473±0.0778,0.5192±0.0526, respectively, for the PDR group. For the control group, the density of each layers were 0.5919±0.0704, 0.6301±0.0527, 0.5691±0.0169, respectively. The macular blood flow density was significantly different in the superficial retinal layer, deep retinal layer and choroidal capillary layer between the control group and the NPDR group, as well as the PDR group and the DR group(total P<0.001). Statistically significant difference was found between the NPDR group and the PDR group in the deep retina layer(P=0.029), but not in the superficial retina layer and choroid capillary layer(P=0.236, 0.268).

CONCLUSION: Compared with the control group, the macular blood flow density of superficial retinal layer, deep retinal layer and choroidal capillary layer in the patients with diabetic retinopathy decreased significantly. It indicated that the macular ischemia existed in both retina and choroid. By quantitatively measurement of the macular blood flow, OCTA may be used for monitoring the progression of diabetes, and early detection of diabetic retinopathy.