The possibilities of optical coherence tomography of the anterior segment in the angio mode (AS-OCTA) in the diagnosis and tactics of surgical treatment of corneal diseases

Purpose. To describe three clinical cases of corneal vascularization of different etiologies, to evaluate the possibilities of the method of optical coherence tomography of anterior segment in the mode of angiography (AS-OCTA) in diagnostic and selection of treatment strategies of corneal diseases, as well as to provide diagnostic protocol. Material and methods. For the first time AS-OCTА was performed at the S. Fyodorov Eye Microsurgery (Moscow). The presented clinical cases included three patients with different pathologies of the anterior segment of the eye: postherpetic neovascularization, superficial epithelial fibroplasia and limbal stem cell deficiency syndrome (LSCD). The scan was performed on an Avanti xR optical coherence tomography device (Optovue Inc. Fremont, California, USA) in the «OCT» and «Angio OCT» modes using the AngioVue program and the SSADA algorithm. Results. In the presented clinical cases, the use of AS-OCTA makes possible to accurately assess the depth, area and architectonics of the vessels, and helps to determine the tactics of surgical treatment and type of keratoplasty. However, the disadvantages of this technique include the complexity and long time required for its implementation, as well as the appearance of a large number of artifacts even with minimal eye movement of patients. At the same time, in the presence of a qualified operator and with proper compliance with the patient, it is possible to obtain valuable diagnostic data. Conclusion. Our study is the first in the Russian Federation to demonstrate the use of anterior segment OCT angiography to visualize the corneal vasculature and provide a protocol for performing it on an Avanti xR optical coherence tomograph. In this preliminary study of patients with corneal neovascularization, we regard the results obtained using AS-OCTA as promising for non-invasive vascular imaging, in particular, before and after the treatment of various conditions with corneal neovascularization. Key words: cornea, neovascularization, limbal stem cell deficiency, anterior segment optical coherence tomography, angiography, corneal limbal vasculature