Value of Optical Coherence Tomography Angiography in Neuroophthalmology

Abstract

Within the last few years, optical coherence tomography angiography (OCTA) has been one of the most intensively investigated developments in ophthalmic research. As a non-invasive imaging tool, it can visualise retinal, choroidal and peripapillary blood flow and was first introduced in retinology. Recently, OCTA has received increasing attention in neuro-ophthalmological diagnostic testing. Special consideration has been given to diseases in which vascular pathogenesis is discussed, such as non-arteritic and arteritic anterior ischemic optic neuropathy (NAION and AAION). Numerous studies have demonstrated rarefication of the peripapillary vascular network and reduced blood flow in NAION and AAION patients compared to healthy patients. The extent of the vascular damage correlates with the severity of optic atrophy. Similar findings also apply to optic atrophy from other causes (e.g., optic nerve head drusen, hereditary optic neuropathy, etc.). However, the exact causal relationships between optic neuropathy and blood flow reduction remain unclear and must be addressed in future investigations. In some diseases, OCTA also seems to be of differential diagnostic value. In haemangioblastomas, it has provided relevant information, especially in large and broad-based findings, and may represent the haemangioblastoma-typical vascular networks and the afferent vessels. This review summarises new information from OCTA studies on neuro-ophthalmic diseases, and questions their relevance and value in clinical use. In the future, it can be expected that OCTA will provide standard values through longitudinal studies with larger numbers of cases that more relevant changes in blood flow in a wide variety of clinical pictures will be analysed more profoundly and will possibly contribute to differential diagnostic and therapeutic studies.