目的：观察单侧视网膜分支静脉阻塞(BRVO)患者视网膜神经纤维层(RNFL)厚度，视盘周围放射状毛细血管(RPC)密度的变化，并进一步分析RPC密度与RNFL厚度的关系。

方法：观察性研究。选取2020-10/2022-01在秦皇岛市第一医院眼科确诊的单侧BRVO患者37例，37只患眼为单侧BRVO组，37只对侧健眼为对侧健眼组，同时期无眼部疾病健康者35名35眼(均选取右眼入组)作为健康对照组。所有参与者双眼均行最佳矫正视力、眼压、眼前节、眼底及光相干断层扫描血管成像(OCTA)检查。使用OCTA设备自带软件测量黄斑中心凹厚度(CMT)、RNFL厚度和视盘中心到动静脉交叉点的距离(DAVD)。采用优化的U-net算法剔除视盘周围大血管后再计算RPC密度。比较三组间CMT、RNFL厚度、RPC密度，并分析RPC密度与CMT、RNFL厚度、DAVD之间的相关性。

结果：单侧BRVO组患眼CMT、RNFL厚度较对侧健眼组和健康对照组显著增厚(均P<0.05)； 对侧健眼组CMT、RNFL厚度与健康对照组比较均无差异(均P>0.05)。单侧BRVO组患眼RPC密度较对侧健眼组增加，较健康对照组减少，但均无差异(均P>0.05)，而对侧健眼组RPC密度较健康对照组减少(P<0.05)。单侧BRVO组患眼RPC密度与CMT无相关性(P=0.960)，与RNFL厚度呈正相关(r=0.401，P=0.014)，与DAVD呈负相关(r=-0.339，P=0.040)。

结论：BRVO患眼视盘区RNFL明显增厚、RPC密度无明显变化。RPC密度与RNFL厚度呈正相关，说明RNFL厚度可作为分析研究RPC密度损伤程度的监测指标。

METHODS: Observational study. Totally 37 patients with unilateral BRVO diagnosed at the ophthalmology department of First Hospital of Qinhuangdao from October 2020 to January 2022 were selected, the 37 affected eyes were the unilateral BRVO group, and 37 fellow healthy eyes were the contralateral unaffected group, and 35 healthy individuals(35 right eyes were selected)without ocular diseases during the same period were selected as the normal control group. The best corrected visual acuity, intraocular pressure, anterior segment, fundus and optical coherence tomography angiography(OCTA)were examined in both eyes of all BRVO patients and healthy individuals. The central macular thickness(CMT), the RNFL thickness, and the optic disc-AV crossing distance(DAVD)were measured by built-in software of the OCTA equipment. The optimized U-net algorithm was used to eliminate the large blood vessels, and then the RPC density was calculated. The CMT, RNFL thickness and RPC density were compared among the three groups. And the correlations of the RPC density with the CMT, RNFL thickness, and the DAVD were investigated.

RESULTS: Compared with the contralateral unaffected group and the normal control group, the CMT and the RNFL thickness were significantly thickened in the unilateral BRVO group(all P<0.05); there were no statistical differences in the CMT and the RNFL thickness between the contralateral unaffected group and the normal control group(all P>0.05). The RPC density in the unilateral BRVO group increased compared with the contralateral unaffected group and decreased compared with the normal control group, but there was no statistically difference(all P>0.05). However, the RPC density in the contralateral unaffected group decreased compared with the normal control group(P<0.05). The RPC density in the unilateral BRVO group was not correlated with the CMT(P=0.960), but positively correlated with the RNFL thickness(r=0.401, P=0.014)and negatively correlated with the DAVD(r=-0.339, P=0.040).

CONCLUSION: The RNFL thickened significantly and the RPC density did not change significantly in the optic disc area of BRVO patients. The RPC density is positively correlated with the RNFL thickness, indicating that the RNFL thickness can be used as a monitoring indicator to analyze and study the damage degree of the RPC density.