Supplementary Material for: Differentiating ischemic optic neuropathy from glaucoma using diagnostic tests

Introduction: Anterior ischemic optic neuropathy (AION) can mimic glaucoma and consequently cause difficulties in differential diagnosis. The purpose of this paper is to summarize differences in diagnostic tests that can help perform a correct diagnosis.
Methods: The search strategy was performed according to the PRISMA 2009 guidelines and four databases were used: Medline, Embase, Web of Science and Cochrane. 772 references were eligible; 39 were included after screening with respect to inclusion criteria that included English language and published in the 20 years before search date.
Results: Ninety percent (n=35) of included studies used optical coherence tomography (OCT). Glaucomatous eyes had a significantly greater cup area, volume and depth, cup-to-disc ratio, and a lower rim volume and area, and a thinner Bruch’s Membrane opening-minimum rim width. Retinal nerve fibre layer (RNFL) thinning in glaucomatous eyes occurred primarily at the superotemporal, inferotemporal and inferonasal sectors, while AION eyes demonstrated mostly superonasal thinning. Glaucoma eyes showed greater macular ganglion cell layer thickness, except at the inferotemporal sector. OCT-angiography measurements demonstrated a significant decrease in superficial and deep macular vessel density (VD) in glaucoma compared to AION with similar degree of visual field (VF) damage; and the parapapillary choroidal VD was spared in AION eyes compared to glaucomatous eyes.
Conclusion: By use of OCT imaging, optic nerve head (ONH) parameters seem most informative to distinguish between glaucoma and AION. Although both diseases affect the RNFL thickness, it seems to do so in different sectors. Differences in structure and vascularity of the macula can also help in making the differential diagnosis.

引言：前部缺血性视神经病变（Anterior ischemic optic neuropathy, AION）的临床表现与青光眼相似，因此二者的鉴别诊断存在一定难度。本研究旨在总结可辅助正确诊断的各类检查手段间的差异。
方法：本研究的检索策略遵照PRISMA 2009指南制定，共检索了Medline、Embase、Web of Science及Cochrane四个数据库。初筛符合条件的参考文献共772篇，随后依据纳入标准（文献语言为英文且发表于检索日期前20年内）进行筛选，最终纳入39篇文献。
结果：纳入的研究中有90%（n=35）采用了光学相干断层扫描（optical coherence tomography, OCT）技术。青光眼患眼的视杯面积、容积与深度、杯盘比均显著更高，而盘周缘容积与面积更小，且Bruch膜开口-最小盘周缘宽度更薄。青光眼患眼的视网膜神经纤维层（retinal nerve fibre layer, RNFL）变薄主要累及颞上、颞下及鼻下象限，而前部缺血性视神经病变患眼则主要表现为鼻上象限变薄。青光眼患眼的黄斑神经节细胞层厚度更高，仅颞下象限除外。光学相干断层扫描血管造影（OCT-angiography）测量结果显示，在视野（visual field, VF）损害程度相似的情况下，青光眼患眼的浅层及深层黄斑血管密度（vessel density, VD）较前部缺血性视神经病变患眼显著降低；且与青光眼患眼相比，前部缺血性视神经病变患眼的视盘旁脉络膜血管密度未出现明显丢失。
结论：借助光学相干断层扫描成像，视盘（optic nerve head, ONH）相关参数似乎是区分青光眼与前部缺血性视神经病变最具诊断价值的指标。尽管两种疾病均会导致视网膜神经纤维层厚度改变，但其变薄的象限分布存在差异。黄斑区结构与血管分布的差异同样可为二者的鉴别诊断提供帮助。