Type 4 Macular Neovascularization (NV): A New Member of the Optical Coherence Tomography (OCT) Classification of NV Age-Related Macular Degeneration (AMD).

Purpose: To describe the clinical and multimodal imaging features of a novel form of macular neovascularization (MNV), designated Type 4 MNV, defined by mixed Type 1 and Type 2 neovascularization (NV), extensive intraretinal anastomotic NV, and central posterior hyaloid fibrosis (CPHF).

Methods: This multicenter retrospective observational case series included patients with neovascular age-related macular degeneration (AMD) exhibiting both Type 1 and 2 MNV and an overlying anastomotic intraretinal NV network. This was confirmed with OCT and OCT angiography (OCTA). Demographics, baseline visual acuity (VA), and OCT imaging biomarkers including the hyperreflective oblique band (HOB) sign, CPHF, epiretinal membrane (ERM), and OCTA NV subtype were assessed.

Results: Eleven eyes from eleven patients (mean age: 76.9 years; 36.4% female) met inclusion criteria. Baseline VA was logMAR 1.56 ± 0.45 (≈20/630) and 90.9% of subjects presented with severe visual loss. All eyes showed the HOB sign. CPHF was observed in 81.8% (9/11 subjects). ERM with radial traction was present in 81.8%. OCTA illustrated mixed Type 1 and 2 MNV with a prominent overlying intraretinal anastomotic network extending into the preretinal space.

Conclusion: Type 4 MNV represents a distinct AMD phenotype with aggressive anatomical features including mixed Type 1 and 2 MNV, inner retinal and preretinal proliferation and anastomosis and retinal disorganization. The visual prognosis is invariably poor with recalcitrance to anti-VEGF therapy. The recognition of this signature NV lesion subtype further refines the MNV classification system and can impact therapeutic strategies for neovascular AMD.