Abstract
The emergence of pachychoroid disease is changing the concept of age-related macular degeneration (AMD). The concept of pachychoroid diseases was developed through clinical observation of multimodal images of eyes with AMD and central serous chorioretinopathy; however, recent genetic studies have provided a proof of concept for pachychoroid spectrum disease, which should be differentiated from drusen-driven AMD. The genetic confirmation of pachychoroid concept further provides novel viewpoints to decode previously reported findings, which facilitates an understanding of the true nature of pachychoroid diseases and AMD. The purpose of this review was to elucidate the relationship between pachychoroid diseases and AMD by interpreting previous findings on pachychoroid diseases and AMD from the novel viewpoints of genetic associations. We confirmed that previous genetic studies supported the concept of pachychoroid diseases. From a genetic viewpoint, the presence of thick choroid and the presence of choroidal vascular hyperpermeability were important characteristics of pachychoroid spectrum diseases. Previous studies have also suggested the classification of polypoidal choroidal vasculopathy (PCV) into two subtypes, pachychoroid neovasculopathy and drusen-driven PCV. Genetic viewpoints will be beneficial to rearrange subtypes of drusen-driven AMD and pachychoroid spectrum diseases. Further genetic studies are needed to investigate pachyvessels, pachydrusen and the significance of polypoidal lesions in pachychoroid neovasculopathy and drusen-driven AMD/PCV.
Highlights
The concept of pachychoroid spectrum diseases has been established within the past 10 years [1,2,3]and has been changing the diagnosis and concept of age-related macular degeneration (AMD).Pachychoroid diseases develop in eyes with thick choroid in which pachychoroid induces various diseases such as central serous chorioretinopathy (CSC), pachychoroid pigment epitheliopathy, pachychoroid neovasculopathy, and pachychoroid geographic atrophy (GA)
When we re-examined Japanese neovascular AMD patients who were diagnosed according to the criteria used before the introduction of the pachychoroid concept, we found that at least 20% of AMD patients had to be diagnosed as eyes with choroidal neovascularization (CNV) that was secondary to pachychoroid or pachychoroid neovasculopathy [4]
The effect of ARMS2 gene on the development of neovascular AMD can be represented by the difference/ratio of the risk allele frequencies between neovascular AMD (0.57 or 0.60) and controls (0.39 or 0.37), while the effect of ARMS2 gene on the development of pachychoroid neovasculopathy can be represented by the difference/ratio of the risk allele frequencies between pachychoroid neovasculopathy (0.51) and controls
Summary
The concept of pachychoroid spectrum diseases has been established within the past 10 years [1,2,3]. Pachychoroid diseases develop in eyes with thick choroid in which pachychoroid induces various diseases such as central serous chorioretinopathy (CSC), pachychoroid pigment epitheliopathy, pachychoroid neovasculopathy, and pachychoroid geographic atrophy (GA). When we re-examined Japanese neovascular AMD patients who were diagnosed according to the criteria used before the introduction of the pachychoroid concept, we found that at least 20% of AMD patients had to be diagnosed as eyes with choroidal neovascularization (CNV) that was secondary to pachychoroid or pachychoroid neovasculopathy [4]. Our recent study using machine learning suggested that 46% of previously diagnosed AMD in Japanese patients had to be diagnosed as pachychoroid neovasculopathy [5]. Retina specialists have accepted the concept of pachychoroid spectrum disease since its proposal
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