Pachychoroid neovasculopathy: A comparative review on pathology, clinical features, and therapy

There have been major changes in our understanding of choroidal diseases in the last decade owing to multiple retinal and choroidal imaging related advances. A major conceptual pivot is establishment of pachychoroid and its spectrum of clinical disorders: pachychoroid pigment epitheliopathy, central serous chorioretinopathy, pachychoroid neovasculopathy, polypoidal choroidal vasculopathy/aneurysmal type 1 neovascularization, peripapillary pachychoroid syndrome, and focal choroidal excavation. However, considerable overlaps in manifestations and therapeutics of these disorders make differentiation amongst them difficult. This review is focused on pathogenesis and clinical aspects of pachychoroid neovasculopathy (PNV). Since PNV was defined as a separate entity around 5 years ago, there have been numerous contrasting observations surrounding it. We review and summarize these studies, and also compare PNV with other disorders of the pachychoroid spectrum in detail. There are important differences between etiologies of neovascular age related macular degeneration and PNV. Yet the current treatment strategies for PNV have been extrapolated from the trials for the former. Future research needs to validate this assumption with long-term results.