Type 4 Macular Neovascularization in a Consecutive Age-Related Macular Degeneration Cohort: Prevalence and Multimodal Imaging Findings

<title>Abstract</title> <p>Background To determine the prevalence of type 4 macular neovascularization (MNV) in an age-related macular degeneration (AMD) cohort, the applicability of the proposed multimodal imaging criteria in an independent center was assessed, and the clinical and imaging features were characterized. Methods 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 classified as definite, probable, or non–Type 4 MNVs according to predefined multimodal imaging criteria. Prevalence was calculated at the patient and eye levels with exact 95% Clopper–Pearson confidence intervals (CIs). Results The prevalence of definite type 4 MNV 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). OCTA demonstrated the characteristic flow pattern in all definite cases. During follow-up, HOB, CPHF, and PHCH remained stable, whereas exudative activity varied. Conclusions Type 4 MNV is a rare but distinct AMD phenotype. Structural OCT is suitable for screening, whereas OCTA is essential for definitive diagnosis. Our findings support the applicability of the proposed multimodal imaging criteria in an independent center and further characterize the clinical and imaging features of type 4 MNVs.</p>