Review of type 3 macular neovascularization in age-related macular degeneration: no DRAMA (Deep Retinal Age-related Microvascular Anomalies)

Abstract

Type 3 macular neovascularization (MNV) is a unique form of neovascular age-related macular degeneration (AMD) that presents distinct pathogenetic features, clinical manifestations, and prognostic considerations when compared to types 1 and 2 MNV. Insights gained from clinicopathological correlations, bridging in vivo examination techniques with ex vivo histological analysis, have significantly enhanced our comprehension of this MNV phenotype, shaped current management strategies and influenced future directions for therapeutics. The particularities of type 3 MNV, which may largely stem from its origin from the retinal vasculature, are critically important for predicting the disease course. Our current understanding suggests that type 3 MNV occurs in response to retinal pigment epithelium (RPE) disruption and photoreceptor loss when neovessels originating from the deep capillary plexus are accompanied by activated Müller glia as they infiltrate sub-retinal pigment epithelium basal laminar deposits. Dysregulation of angiogenic and angiostatic factors are thought to play a key role in its pathogenesis. The prognosis for type 3 MNV is likely bilateral involvement and progression towards macular atrophy. It may be imperative for practitioners to distinguish type 3 MNV from other mimicking pathologies such as intraretinal microvascular anomalies, which are also part of the type 3 disease spectrum. For instance, deep retinal age-related microvascular anomalies (DRAMA) may present with similar features on multimodal imaging yet may necessitate distinct management protocols. Distinguishing between these conditions may be vital for implementing tailored treatment regimens and improving patient outcomes in the diverse landscape of AMD phenotypes in the future.