Dark halo, a new biomarker in macular neovascularization: comparison between OCT angiography and ICGA—a pilot prospective study

Abstract

Purpose To compare optical coherence tomography angiography (OCTA) and indocyanine green angiography (ICGA) in terms of reliability in detecting dark halo in patients affected by age-related macular degeneration (AMD) complicated with type 1 macular neovascularization (MNV). Methods Eighty-nine eyes of 89 patients were analyzed at the University of Naples Federico II between January 2018 and October 2021. Each patient underwent a complete ophthalmological evaluation including fluorescein angiography, ICGA, spectral domain optical coherence tomography (SD-OCT), and OCTA. OCTA and ICGA images of dark halo were compared. The paired Student’s test and intraclass correlation coefficients were used to evaluate the differences in dark halo measurements between OCTA and ICGA images. Results Thirty-six eyes of 36 patients were included in this prospective study. Dark halo area was significantly larger in OCTA than in ICGA (1.49 ± 1.8 mm2 vs. 0.54 ± 0.5 mm2; p = 0.001). Moreover, the agreement between the two types of devices for measuring dark halo areas was poor, with a low intraclass coefficient correlation (0.397). Conclusion OCTA could be a useful and necessary tool to investigate dark halo in neovascular AMD due to its ability to visualize the areas of reduced vessel density around MNV in greater detail compared to ICGA. Clinical trial registration ClinicalTrials.gov Identifier: NCT05108285

Structural and clinical changes in previously treated type 1 macular neovascularization in non-responder AMD eyes switched to brolucizumab

“…21 Nowadays, aiming to understand the pathogenesis of exudative AMD better, the spotlights tend to be focused on active biomarkers of disease detected by OCT and OCT angiography. [22][23][24] Brolucizumab, recently approved by the FDA, may play a vital role in AMD non-responders. 5 To the best of our knowledge this is the first prospective study analyzing SHRM and other structural activity biomarkers in type 1 nAMD after brolucizumab injections.…”

“…Nowadays, aiming to understand the pathogenesis of exudative AMD better, the spotlights tend to be focused on active biomarkers of disease detected by OCT and OCT angiography. 22–24…”

Macular Imaging

“…Studies have attempted to use the aforementioned OCTA features as biomarkers to determine MNV lesion activity criteria as either active or inactive [77,80]. A recent biomarker termed "dark halo" is defined as a hypofluorescent choriocapillaris area surrounding the MNV, characterized by a flow deficit detected by OCTA [85]. Rispoli et al have quantified dark halo (i.e., choriocapillaris vascular density changes) around MNV before and after anti-vascular endothelial growth factor (VEGF) injections using OCTA [70].…”

“…Microperimetry is a method of choice for residual visual function assessment. Some macular diseases, including age-related macular degeneration (AMD), diabetic macular edema (DME), Stargardt disease, macular hole, idiopathic macular telangiectasia, and central serous chorioretinopathy, are studied using microperimetry [85,88]. Visual rehabilitation training benefits from microperimetry.…”