目的

探讨青光眼患者视神经形态结构变化与血流密度及血氧代谢改变的关系。

方法

2016年2月至2019年10月于首都医科大学附属北京同仁医院招募原发性开角型青光眼患者108例（210只眼）和健康对照组受试者110例（220只眼）。其中，男性128例（252只眼），女性90例（178只眼）；年龄45～66岁，平均年龄（55.1±7.5）岁。使用光学相干断层扫描血管成像（OCTA）测量视盘全周血管参数；使用光学相干光断层扫描（OCT）测量视盘周围视网膜神经纤维层（rNFL）平均厚度；使用视网膜血氧计测量视网膜动静脉血氧饱和度。使用Humphrey视野分析仪检测视野的平均缺损（MD）。眼压、RNFL厚度、MD、视网膜血管参数及视网膜血氧饱和度采用Kolmogorov-Smirnov方法检验符合正态分布，以±s表示，组间比较采用独立样本t检验，多组比较采用单因素方差分析。视网膜血管参数与视网膜血氧饱和度及青光眼严重程度的关系采用Pearson相关性分析。

结果

青光眼组和对照组盘周放射状毛细血管（rPC）全部血管密度、视盘内部血管密度及盘周血管密度分别为（40.5±8.5）%、（42.8±9.5）%、（41.9±9.9）%、（49.6±3.8）%、（50.6±5.6）%及（51.5±4.4）%，差异有统计学意义（t＝-2.382，-2.543，-2.074；P＜0.05）。轻中重度青光眼患者全部视盘血管密度分别为（47.4±3.8）%、（41.8±5.5）%及（32.8±6.3）%，差异有统计学意义（F＝143.52，P＜0.05）。RPC视盘全部血管密度和盘周血管密度与青光眼的视野MD呈正相关，其相关性具有统计学意义（r＝0.784，P＜0.05）；盘周血管密度与视野MD呈正相关，其相关性具有统计学意义（r＝0.742，P＜0.05）。RNFL厚度及盘沿面积与青光眼视野MD呈正相关，其相关性具有统计学意义（r＝0.625，P＜0.05）；盘沿面积与视野MD呈正相关，其相关性具有统计学意义（r＝0.544，P＜0.05）。青光眼组和对照组患者的全部视网膜静脉血氧饱和度、上半侧视网膜静脉血氧饱和度及下半侧视网膜静脉血氧饱和度的均值分别为（62.9±10.4）%、（63.8±11.0）%、（59.7±11.9）%、（57.3±6.5）%、（59.2±7.1）%及（54.0±8.6）%，差异有统计学意义（t＝3.214，2.942，2.348；P＜0.05）。青光眼组和对照组患者全部视网膜动静脉血氧饱和度差值、上半侧视网膜动静脉血氧饱和度差值及下半侧视网膜动静脉血氧饱和度差值的均值分别为（30.2±13.1）%、（28.3±12.6）%、（32.4±11.2）%、（34.2±5.4）%、（32.6±7.9）%及（38.2±8.9）%，差异有统计学意义（t＝-2.535，-1.983，-2.164；P＜0.05）。青光眼患者的视网膜动静脉血氧饱和度差值降低。轻度和重度青光眼组患者的视网膜脉血氧饱和度分别为（92.0±7.1）%和（91.7±10.2）%，差异无统计学意义（t＝-1.457，P＞0.05）。轻度和重度青光眼组患者的视网膜静脉平均血氧饱和度分别为（64.6±10.1）%和（67.9±8.5）%，差异有统计学意义（t＝2.093，P＜0.05）。轻度和重度青光眼组患者的视网膜动静脉血氧饱和度差值分别为（27.2±8.1）%和（23.6±6.7）%，差异有统计学意义（t＝-2.544，P＜0.05）。视网膜静脉血氧饱和度与视杯体积、杯盘比、视野MD、RNFL厚度及盘沿面积相关，其相关性具有统计学意义（r＝0.333，0.317，-0.459，-0.337，-0.319，P＜0.05）。青光眼组和对照组下半侧视野异常伴上半侧视野正常患者上半侧视野对应的下方视网膜RNFL厚度值分别为（73.0±8.3）μm和（111.0±6.9）μm，差异有统计学意义（t＝-2.458，P＜0.05）；黄斑下方GCC值分别为（74.0±6.4）μm和（99.0±5.8）μm，差异有统计学意义（t＝-2.094，P＜0.05）；OCTA盘周下方RNFL层的血管密度值分别为（41.0±6.2）%和（51.0±4.5）%，差异有统计学意义（t＝-2.213，P＜0.05）；下方视网膜静脉血氧饱和度分别为（59.0±6.7）%和（54.0±8.6）%，差异有统计学意义（t＝2.274，P＜0.05）。

结论

OCTA检测的青光眼视盘血管密度和视网膜静脉血氧饱和度变化与视野改变以及OCT检测的神经结构变化相关。在青光眼神经损伤和视野损害前已有视盘血管密度降低以及视网膜静脉血氧饱和度上升，视网膜神经组织代谢降低，血管因素是青光眼神经损伤进展的原因。

Objective

The aim of this study is to explore the relationship between damages in optic nerve morphology and changes in blood flow density and blood oxygen metabolism in glaucoma.

Methods

From February 2016 to October 2019，108 patients（210 eyes） with primary open-angle glaucoma and 110 healthy control subjects（220 eyes）were recruited from Beijing Tongren Hospital affiliated with Capital Medical University.Among them，there were 128 males（252 eyes）and 90 females（178 eyes），with an average age of（55.1±7.5）years old（ranging from 45 to 66 years old）.Optical coherence tomography angiography（OCTA）was used to measure vascular parameters around the optic disc and inner the optic disc.The average thickness of the retinal nerve fiber layer（rNFL）around the optic disc was used to measure by optical coherence tomography（OCT）.the retinal arterial and venous oxygen saturation was used to measure by retinal oximeter.The mean defect（MD）of visual field was to detect using Humphrey visual field analyzer.The Kolmogorov Smirnov statistical method was used to test intraocular pressure，RNFL thickness，visual field MD，parameters of retinal blood vessels and retinal oxygen saturation as normal distribution，and expressed as ±s，and compared by independent sample t test for intergroups，and one-way analysis of variance for multiple groups.The relationship between retinal vascular parameters，retinal oxygen saturation，and the severity of glaucoma were analyzed using Pearson correlation analysis.

Results

Comparing between the glaucoma and the control group，the whole optic disc vascular density，as well as the vascular density inside the optic disc and radial peripapillary capillary（rPC），were（40.5±8.5）%，（42.8±9.5）%，（41.9±9.9）%，（49.6±3.8）%，（50.6±5.6）%，and（51.5±4.4）%，respectively，with statistically significant differences（t＝-2.382，-2.543，-2.074；P＜0.05）.The whole optic disc vascular density of patients with mild，moderate，and severe glaucoma was（47.4±3.8）%，（41.8±5.5）%，and（32.8±6.3）%，respectively，with statistically significant differences between the groups（F＝143.52，P＜0.05）.The whole vascular density of optic disc and the radial peripapillary capillary were positively correlated with the visual field MD of glaucoma，and the correlation was statistically significant（r＝0.784，P＜0.05）.There was positive correlation between the radial peripapillary capillary and visual field MD，and the correlation was statistically significant（r＝0.742，P＜0.05）.RNFL thickness and the optic rim area were positively correlated with the visual field MD of glaucoma，and the correlation was statistically significant（r＝0.625，P＜0.05）.The optic rim area was positively correlated with visual field MD，and the correlation was statistically significant（r＝0.544，P＜0.05）.The mean values of total retinal venous oxygen saturation，the upper retinal venous oxygen saturation，and the lower retinal venous oxygen saturation in the glaucoma group and control group were（62.9±10.4）%，（63.8±11.0）%，（59.7±11.9）%，（57.3±6.5）%，（59.2±7.1）%，and（54.0±8.6）%，respectively，showing statistical significance（t＝3.214，2.942，2.348；P＜0.05）.The mean differences of retinal arterial and venous oxygen saturation in the total，the upper and the lower retina in the glaucoma group and the control group were（30.2±13.1）%，（28.3±12.6）%，（32.4±11.2）%，（34.2±5.4）%，（32.6±7.9）%，and（38.2±8.9）%，respectively.The difference was statistically significant（t＝-2.535，-1.983，-2.164；P＜0.05）.The difference of retinal arterial and venous oxygen saturation in glaucoma was reduced.The retinal artery oxygen saturation in the mild glaucoma group and the severe glaucoma group were（92.0±7.1）% and（91.7±10.2）%，respectively，showing no statistically significant difference（t＝-1.457，P＞0.05）.The average retinal venous oxygen saturation in the mild glaucoma group and the severe glaucoma group were（64.6±10.1）%and（67.9±8.5）%，respectively，with statistically significant difference（t＝2.093，P＜0.05）.The difference of retinal arterial and venous oxygen saturation in the mild glaucoma group and the severe glaucoma group were（27.2±8.1）% and（23.6±6.7）%，respectively，showing statistically significant difference（t＝-2.454，P＜0.05）.Retinal venous oxygen saturation was correlated with cup volume，cup to disc ratio，visual field MD，RNFL thickness，and optic rim area，and the correlation showing statistically significant（r＝0.333，0.317，-0.459，-0.337，-0.319，P＜0.05）.The peripapillary RNFL thickness in the lower retina corresponding to the upper visual field of patients with abnormal lower visual field and normal upper visual field in the glaucoma group and control group were（73.0±8.3）μm and（111.0±6.9）μm，respectively，the difference showing statistically significant（t＝-2.458，P＜0.05）.The inferior macula ganglion cell complex（GCC）values in the glaucoma and control group were（74.0±6.4）μm and（99.0±5.8）μm，respectively，and the difference was statistically significant（t＝-2.094，P＜0.05）.The inferior peripapillary vascular density in the glaucoma group and control group were（41.0±6.2）% and（51.0±4.5）%，respectively，with statistically significant differences（t＝-2.213，P＜0.05）.The inferior retinal venous oxygen saturation in the glaucoma group and control group were（59.0±6.7）% and（54.0±8.6）%，respectively，with statistically significant differences（t＝2.274，P＜0.05）.

Conclusions

Changes in optic disc vascular density detected with OCTA and retinal venous oxygen saturation in glaucoma are correlated with changes of visual field and RNFL thickness measured with OCT.Before glaucomatous optic nerve damage and visual field loss，decreasing in optic disc vascular density and increasing in retinal venous oxygen saturation have been found，indicating decreased metabolism of retinal nerve tissue.Vascular factor is one of the reasons of the progression of glaucomatous opitc nerve damage.