Research progress in imaging features of pachychoroid spectrum diseases

Pachychoroid spectrum diseases(PSD)have been defined as a group of diseases with similar choroidal features and pathological processes, such as central serous chorioretinopathy(CSC), polypoidal choroidal vasculopathy(PCV), etc. The main features are the changes in the thickness of vascular layers of the choroid and increasing vascular permeability. The development of modern ophthalmic imaging devices represented by optical coherence tomography angiography(OCTA)allowed intuitive investigation of the changes in the choroidal vascular layers, which gives a new insight into the pathogenesis of this spectrum diseases. This article summarizes the common clinical characteristics of healthy individuals and PSD and reviews the latest imaging findings. Whether each type of PSD is a phenotype of the same disease at different stages or other with similar characteristics was discussed from different perspectives, such as genetic background and anatomical structure, providing a reference for the study of pathogenesis, early clinical diagnosis, and prevention and treatment of this disease.