青光眼视网膜血氧饱和度与结构功能损害程度的相关分析

目的比较青光眼与正常人视网膜血氧饱和度的差异，分析青光眼患者中视网膜血氧饱和度与结构功能损害程度的相关性。方法病例对照研究。选取原发性开角型青光眼患者28例（35眼）为青光眼组，记录患者年龄、性别、眼压、血压、杯盘比，并进行中心30°阈值视野检测和光学相干断层扫描（OCT）检测视乳头旁视网膜神经纤维层（RNFL）厚度，并纳入27例（41眼）正常人作为对照组，采用视网膜血氧饱和度分析仪测量青光眼患者和正常人视网膜血管血氧饱和度。2组动静脉血氧饱和度差异比较采用独立样本t检验。采用Pearson或Spearman秩相关分析对青光眼组视网膜血氧饱和度与年龄、眼压、血压、杯盘比、视野平均缺损（MD）、视野指数（VFI）、视乳头旁RNFL厚度进行相关分析。结果青光眼组与正常对照组的视网膜动脉血氧饱和度差异无统计学意义，青光眼组静脉血氧饱和度较对照组高（t=4.017，P＜0.001），动静脉血氧饱和度差值较小（t=-4.431，P＜0.001）。青光眼组视网膜动脉血氧饱和度、静脉血氧饱和度、动静脉血氧饱和度差值与年龄、眼压、血压均无线性相关性。视网膜动脉血氧饱和度与杯盘比、视野MD、VFI、视乳头旁RNFL厚度等均无线性相关。视网膜静脉血氧饱和度与杯盘比、视野MD值呈正相关（杯盘比：r=0.418，P=0.012；视野MD：r=0.504，P=0.002），与RNFL厚度、VFI呈负相关（RNFL：r=-0.514，P=0.002；VFI：r=-0.470，P=0.004）。视网膜动静脉血氧饱和度差值与杯盘比、视野MD均呈负相关（杯盘比：r=-0.390，P=0.021；视野MD：r=-0.478，P=0.004），与VFI、视乳头旁RNFL厚度呈正相关（VFI：r=0.449，P=0.007；RNFL：r=0.385，P=0.022）。结论随着青光眼加重，静脉血氧饱和度增加，动静脉血氧饱和度差值降低。青光眼患者视网膜耗氧量降低可能与视网膜神经组织萎缩有关。

Correlation of retinal vessel oxygen saturation with structural and functional damage in glaucoma

Objective To determine if retinal oxygen metabolism is different in glaucoma patients compared to healthy subjects and to determine if retinal vessel oxygen saturation is correlated with structural and functional damage in glaucoma patients. Methods This case control study included 28 patients (35 eyes) with primary open-angle glaucoma and 27 healthy individuals (41 eyes). Visual fields were measured with a Humphrey field analyzer. Optical coherence tomography (OCT) was performed to detect the thickness of the retinal nerve fiber layer (RNFL) in glaucoma patients. Retinal vessel oxygen saturation was measured in glaucoma patients and healthy individuals with a non-invasive spectrophotometric retinal oximeter. Statistical analysis was performed using independent t-test and Pearson′s correlation. Results There was no significant difference in retinal arteriole oxygen saturation between glaucoma patients and healthy individuals. However, the oxygen saturation in venules was higher and the arteriovenous difference was lower in glaucoma patients (t=4.017, P<0.001; t=-4.431, P<0.001). Retinal arteriolar oxygen saturation was not associated with age, intraocular pressure, blood pressure, cup-to-disc ratio, mean deviation (MD), visual field index (VFI), or RNFL thickness in glaucoma patients. The retinal oxygen saturation in both the venules and arteriovenous (AV) difference was not correlated with age, intraocular pressure, or blood pressure in glaucoma patients. Retinal venous oxygen saturation was positively correlated with the cup-to-disc ratio (r=0.418, P=0.012) and MD (r=0.504, P=0.002) and negatively correlated with RNFL thickness (r=-0.514, P=0.002) and VFI (r=-0.470, P=0.004) in glaucoma patients. On the other hand, the AV difference was negatively correlated with the cup-to-disc ratio (r=-0.390, P=0.021) and MD (r=-0.478, P=0.004) and positively correlated with RNFL thickness (r=0.385, P=0.022) and VFI (r=0.449, P=0.007) in glaucoma patients. Conclusion Severe glaucomatous damage is associated with increased oxygen saturation in venules and a decrease in the AV difference in retinal oxygen saturation, suggesting that reduced retinal oxygen consumption is related to the atrophy of the retinal nerve fibers.