[Fibrovascular transformation of CNV in nAMD after long-term anti-VEGF therapy : Methodological evaluation of quantifying morphological changes].

Background: Under long-term anti-VEGF therapy neovascular age-related macular degeneration (nAMD) may result in fibrovascular transformation of choroidal neovascularization (CNV). So far there is a lack of definitions on how a differentiated quantification of the associated morphological changes can best be carried out. This pilot study aimed to define the most appropriate imaging modalities.

Patients And Methods: In 56 eyes with fibrotic CNV after at least 2 years of anti-VEGF therapy and at least 12 intravitreal anti-VEGF injections, the following imaging modalities were investigated with respect to the delimitation of vascular and fibrous portions of CNV as well as associated atrophy of retinal pigment epithelium (RPE) and disruption of the ellipsoid zone (EZ): multicolor imaging (MC), fundus autofluorescence (FAF), fluorescein angiography (FA) and indocyanine green angiography (ICGA), spectral domain optical coherence tomography (SD-OCT) and OCT angiography (OCTA).

Results: The vascular portion of fibrotic CNV was best visualized by OCTA, the fibrous portion by SD-OCT. The RPE atrophy was best delimitated by FAF, but differentiation was also possible by MC and ICGA. Disruption of the EZ could be delineated by SD-OCT b‑scan.

Conclusion: The use of MC is suitable for visualization of RPE atrophy and the fibrous portion of fibrotic CNV and FAF is suitable for differentiation of RPE atrophy. The SD-OCT can be used to quantify the fibrous portion of CNV; the EZ interruption is delimitable in the b‑scan but not in the transverse structure-scan. The vascular part can best be detected by OCTA.