Assessing the long-term evolution of type 3 neovascularization in age-related macular degeneration using optical coherence tomography angiography.

PURPOSE: To analyze the evolution of type 3 neovascularization in eyes with age-related macular degeneration during anti-vascular endothelial growth factor (VEGF) treatment using optical coherence tomography angiography (OCTA) analysis.

METHODS: Forty-one treatment-naïve eyes (37 patients) with type 3 neovascularization were retrospectively included in the study. The growth and morphological changes in the type 3 lesions, which were recorded using OCTA, were compared across time.

RESULTS: The high-flow signal of the lesion on OCTA was significantly increased at the sub-retinal pigment epithelium (RPE) and the choriocapillaris during anti-VEGF treatment. The detection rate of the flow signal in the sub-RPE increased from 50.0% at baseline and 51.2% at 12 months to 65.9% at 24 months (P = 0.013). The flow signal extending into the choriocapillaris was detected in 0% of the eyes at baseline, 9.8% of the eyes at 12 months, and 17.1% of the eyes at 24 months (P = 0.018). The presence of subretinal drusenoid deposits (SDD) was significantly more frequent in the group with extension into the choriocapillaris (100%) than in the group without (61.8%, P = 0.036). For the four eyes with extension into the choroid, the morphological feature of the lesion on en face OCTA evolved into a tangled vascular network, similar to type 1 neovascularization.

CONCLUSION: OCTA analysis revealed that type 3 neovascularization gradually extended downward toward the sub-RPE and choroid during anti-VEGF treatment. The extension of the lesion into the choriocapillaris, suggesting retinal-choroidal anastomosis, was significantly more frequent in eyes with SDD.