眼轴对原发性开角型青光眼视盘和黄斑血管密度的影响

目的：运用光学相干断层扫描血管成像（OCTA）进行视网膜视盘区和黄斑区血管成像，探讨眼轴对 原发性开角型青光眼（POAG）视盘和黄斑血管密度的影响。方法：病例对照研究。连续收集2019年 6 ─11 月于中山眼科中心确诊的POAG病例，依据眼轴长度分为中等眼轴青光眼组（眼轴范围为 22.51～25.50 mm）和长眼轴青光眼组（眼轴>25.50 mm），并匹配年龄和病情严重程度，所有患者单 眼入组。最后共42例纳入中等眼轴青光眼组，37例纳入长眼轴青光眼组。所有受检者完成视野、光 学相干断层扫描成像（OCT）、OCTA检查。通过OCTA测量视盘周围放射状毛细血管密度（RPC VD） 和黄斑浅层血管密度。采用独立样本t检验、Pearson相关等分析数据。结果：长眼轴青光眼组神 经节细胞复合体（GCC）厚度小于中等眼轴青光眼组（74.5±9.6）μm vs. （80.5±13.6）μm；t=2.244， P=0.028]，但2组视网膜神经纤维层（RNFL）厚度差异无统计学意义。长眼轴青光眼组黄斑全图、 黄斑旁区、黄斑周围区血管密度均小于中等眼轴青光眼组，但仅黄斑周围区颞侧血管密度的差 异有统计学意义（t=2.235，P=0.028）。2组的平均和各象限RPC VD差异均无统计学意义。眼轴与 GCC、黄斑浅层血管密度参数呈负相关（眼轴与GCC：r=-0.333，P=0.003；眼轴与黄斑浅层血管密 度：r=-0.303～-0.282，均P<0.05），与RPC VD无显著相关性（P=0.383）。结论：在病情相近的情 况下，POAG眼轴的延长主要损害黄斑血管，尤其是周边部颞侧血管，对视盘周围微血管无显著 影响。

The Effect of Axial Length on Optic Disc and Macular Vessel Density in Primary Open Angle Glaucoma

Objective: To investigate the effect of axial length on optic disc and macular vessel densities (VDs) in primary open angle glaucoma (POAG) using optical coherence tomography angiography (OCTA). Methods: Patients with POAG were consecutively recruited in this case-control study from June 2019 to November 2019 in Zhongshan Ophthalmic Center. Eyes with POAG were divided into 2 groups based on a medium axial length (ranging 22.51-25.50 mm) and a long axial length (>25.51 mm). Then the two groups were matched by age and severity of glaucoma. Only one eye in each participant was selected. Atotal of 42 eyes of 42 patients were enrolled in the medium axial length group, and 37 eyes of 37 patients were enrolled in the long axial length group. All participants underwent visual field, OCT and OCTA examinations. Both radial peripapillary capillary vessel density (RPC VD) and macular superficial VD were evaluated with OCTA. A Student's t test and Pearson correlation were used for analysis. Results: The ganglion cell complex (GCC) thickness of the long axial-length eyes with glaucoma was lower by a statistically significantly amount than in the medium axial-length eyes with glaucoma (74.5±9.6 μm vs. 80.5±13.6 μm; t=2.244, P=0.028), while there was not a statistically significant difference in retinal nerve fiber layer (RNFL) thickness between these two groups. All macular VD parameters, including whole-image VD, parafoveal VD, perifoveal VD, were lower in the long axial-length eyes than in the medium axial-length eyes. A statistically significant difference was only found in the temporal perifoveal VD (t=2.235, P=0.028). The overall average and all quadrants of RPC VD between groups did not have a statistically significant difference (all P>0.05). Axial length had a statistically significant negative correlation with GCC and macular VD parameters (axial length and GCC: r=0.333, P=0.003; axial length and macular VD parameters: r ranged from -0.333 to -0.282, all P<0.05), while no statistically significant correlation between axial length and RPC VD was found. Conclusions: Axial length elongation in POAG eyes can damage the macular structure and vessel density, while it has little effect on optic disc vessel density.