Anti-VEGF Treatment and Optical Coherence Tomography Biomarkers in Wet Age-Related Macular Degeneration

Abstract

Age-related macular degeneration (AMD) is one of the most common causes of severe visual loss in middle and old-age population, and often leads to serious deterioration in quality of life. Currently, the first-line treatment for neovascular AMD (nAMD) are intravitreal injections of anti-vascular endothelial growth factor (VEGF) medications, including bevacizumab, ranibizumab, and aflibercept and also latest commercially available drug, brolucizumab. During initial examination and imaging and treatment follow-up for patients with nAMD, optical coherence tomography (OCT) is used to predict and assess the therapeutic response and guide the treatment. Several OCT-based biomarkers, including the central subfoveal thickness (CSFT), the presence of intraretinal cysts (IRCs) or subretinal fluid (SRF), and the presence of pigment epithelial detachment (PED), were found to influence baseline visual acuity or visual improvements. Recent analyses of large randomized control trials (RCTs) summarized the usefulness of these OCT-based biomarkers. However, many of these early studies relied on time-domain OCT to evaluate the retinal structures thus providing less precise evaluation of the retinal details. After introduction of spectral-domain OCT (SD-OCT) which provided high resolution images, recent studies offered new insights in specific morphological changes and their different impact on visual function in nAMD. For example, these advancement in resolution offered new classification of IRCs into degenerative and exudative which impacts treatment strategy and final outcome in the treatment of nAMD. Moreover, the recent data disclose a substantial difference between RCTs and real-world studies regarding the response to anti-VEGF therapy. In conclusions, IRCs and PED are associated with poor visual improvement in nAMD in a realworld setting. Both IRCs and SRF responded better than PED to anti-VEGF therapy. These observations mandate large longitudinal studies focusing on the usefulness of these high resolution SD-OCT biomarkers in real-world situations.