Pachydrusen is found in pachychoroid diseases such as polypoid choroidal vasculopathy disease, central serous chorioretinopathy, pachychoroid pigment epitheliopathy and pachychoroid neovasculopathy. The typical choroidal changes of the spectrum are abnormally dilated pachyvessels, choroidal thickening with overlying retinal pigmentary epithelium changes. In this paper, we summarized the clinical manifestations, epidemiology, genetics, and histopathology of the newly named type of drusen, in order to provide the direction for diagnosis and treatment in clinical ophthalmic diseases.