Type 4 macular neovascularization in a consecutive age-related macular degeneration cohort: detected prevalence and multimodal imaging findings

To determine the detected prevalence of type 4 macular neovascularization (MNV) within a retrospectively screened age-related macular degeneration (AMD) cohort and to characterize its clinical, structural, and angiographic features. This single-center retrospective cohort study included 4658 structural OCT examinations from 962 eyes of 500 patients with age-related macular degeneration (AMD). Eyes with structural OCT findings suggestive of type 4 MNV underwent multimodal evaluation via structural OCT and available OCT angiography (OCTA). Cases were categorized as definite, probable, or non–type 4 MNV according to predefined multimodal imaging criteria. Detected prevalence within the screened cohort was calculated at the patient and eye levels with exact 95% Clopper–Pearson confidence intervals (CIs). The detected prevalence of definite type 4 MNV within the entire consecutive AMD cohort was 2.00% (95% confidence interval [CI], 0.96–3.65%) at the patient level and 1.04% (95% CI, 0.50–1.90%) at the eye level. The hyperreflective oblique band (HOB), subretinal hyperreflective material (SHRM), and ellipsoid zone (EZ) loss were present in all the definite cases. Central posterior hyaloid fibrosis (CPHF) was observed in half of the definite cases, whereas the remaining eyes exhibited posterior hyaloid central hyperreflectivity (PHCH). By definition, the OCTA criterion of a continuous flow signal extending from the inner choroid to the preretinal space was fulfilled in all definite cases. During follow-up, HOB, CPHF, and PHCH remained stable, whereas exudative activity varied. Within this consecutive AMD cohort, type 4 MNV was an uncommon phenotype characterized by recognizable structural and angiographic features. Structural OCT was used to identify eyes suspicious for type 4 MNV, whereas designation as definite type 4 MNV required demonstration on OCTA of the continuous flow signal specified in the predefined criteria. Our findings further characterize the clinical, structural, and angiographic features of type 4 MNV in this retrospective cohort.