Our understanding of “pachychoroid disease” has expanded greatly thanks to multimodal clinical imaging technologies. Cross-sectional and en face depth-resolved imaging, such as enhanced depth imaging (EDI) OCT, Swept-Source OCT (SS-OCT), and OCT angiography (OCTa), have enabled a deeper appreciation for the role of the choroid in a wide-range of macular disorders.
Pachychoroid disease is a phenotype encompassing a spectrum of macular conditions which manifest common choroidal findings, and includes pachychoroid pigment epitheliopathy, central serous chorioretinopathy, peripapillary pachychoroid syndrome and focal choroidal excavation. This phenotype of great clinical relevance in that it may predispose patients to macular neovascularization (pachychoroid neovasculopathy). Many patients with pachychoroid disease develop this type 1 neovascularization as a late-stage manifestation. In some eyes, these vessels may form a branching network that can give rise to aneurysmal type 1 neovascularization (polypoidal choroidal vasculopathy).
A younger age and distinct choroidal features of pachychoroid patients distinguishes pachychoroid neovasculopathy from traditionally described neovascular age-related macular degeneration (AMD). Specific choroidal findings on multimodal imaging define the pachychoroid phenotype. Phenotypical biomarkers of pachychoroid include dilated choroidal veins called “ achyvessels”, attenuation of the inner choroid overlying those vessels, choroidal hyperpermeability on indocyanine green angiography (ICGA), and the presence of recently reported pachydrusen over pachyvessels.