Vosborg Fia, Malmqvist Lasse, Hamann Steffen
Department of Ophthalmology, Rigshospitalet, University of Copenhagen, Glostrup, Denmark.
Eur J Ophthalmol. 2020 Mar;30(2):235-244. doi: 10.1177/1120672119858891. Epub 2019 Jun 26.
Diseases of the optic nerve head involving changes in blood flow are common. However, the pathophysiology is not always fully understood. Several non-invasive methods for measuring optic nerve head blood flow are available, but currently no gold standard has been established. Methods for measuring blood flow in optic neuropathies including colour Doppler imaging, retinal function imager, optical coherence tomography angiography and laser speckle flowgraphy are reviewed. Ultrasound colour Doppler imaging is a fast measurement technique where several different parameters, especially the blood flow velocity, can be calculated. Though used for many years in ophthalmology, its use is not standardized and it requires significant observer skills. The retinal function imager is a direct method where the haemoglobin in erythrocytes is visualized and blood flow velocities in retinal vessels are calculated from a series of photos. The technique is not suitable for direct measurement of blood flow within the optic nerve head. Laser speckle flowgraphy uses a laser light which creates a light scatter pattern in the tissue. Particles moving in the area causes changes in the speckle pattern from which a relative blood flow can be estimated. It is, however, not known whether optic nerve head microcirculation is measurable with the technique. Optical coherence tomography angiography uses multiple scans to evaluate blood flow with good reproducibility but often problems with artefacts. The technique is continuously being refined and increasingly used in research as a tool for the study of blood flow in retinopathies and optic neuropathies. Most of the conducted studies are based on small sample sizes, but some of the methods show promising results in an optic nerve head blood flow research setting. Further and larger studies are required to provide standardized and comparable measurements before one or more of the methods can be considered clinical helpful in daily practice.
涉及血流变化的视神经乳头疾病很常见。然而，其病理生理学并不总是被完全理解。有几种测量视神经乳头血流的非侵入性方法，但目前尚未建立金标准。本文综述了包括彩色多普勒成像、视网膜功能成像仪、光学相干断层扫描血管造影和激光散斑血流图在内的视神经病变血流测量方法。超声彩色多普勒成像是一种快速测量技术，可以计算几个不同的参数，尤其是血流速度。尽管在眼科已经使用多年，但其使用并不规范，需要较高的观察者技能。视网膜功能成像仪是一种直接方法，通过它可以观察红细胞中的血红蛋白，并根据一系列照片计算视网膜血管中的血流速度。该技术不适用于直接测量视神经乳头内的血流。激光散斑血流图使用激光在组织中产生光散射图案。该区域内移动的粒子会导致散斑图案发生变化，由此可以估计相对血流。然而，尚不清楚该技术是否可用于测量视神经乳头微循环。光学相干断层扫描血管造影使用多次扫描来评估血流，具有良好的可重复性，但经常存在伪像问题。该技术正在不断改进，越来越多地用于研究视网膜病变和视神经病变中的血流。大多数已开展的研究样本量较小，但其中一些方法在视神经乳头血流研究中显示出有前景的结果。在这些方法中的一种或多种被认为在日常临床实践中有帮助之前，需要进一步开展更大规模的研究，以提供标准化和可比的测量结果。
