The pathogenesis of polypoidal choroidal vasculopathy (PCV) is still controversial. More evidence of clinical and basic research is needed to distinguish PCV from an independent disease to a subtype of age-related macular degeneration. Not only that, there are also many puzzles in the diagnosis, treatment options and prognosis of PCV. In addition to these common problems, we also face a large population with risk factors, a large number of PCV patients with multiple and complex challenges in China. There is a long way to go to reduce the damage effects of PCV on visual function. To fulfil this goal, we need make full use of the huge resources of PCV patients and turn these challenges into opportunities, and contribute the improvement of diagnosis and better understanding of PCV pathogenesis.
Retinal vein occlusion (RVO) is a vascular disease characterized by intraretinal hemorrhage, edema and hard exudation, which is caused by increased retinal vein pressure. OCT angiography (OCTA) has been widely used in the diagnosis of retinal vascular diseases including RVO by virtue of non-invasive, high resolution and stratified display of superficial, deep retinal vessels and quantification of retinal vessel density and non-perfusion area size. OCTA can provide information of retinal microvascular structure and blood perfusion under the condition of disease, it also can be used to evaluate the effect of treatment and changes of retinal circulation during the course of disease follow-up. Although OCTA cannot replace fundus angiography completely, it has brought us more information about the pathogenesis, disease progression and prognostic factors of RVO. It is believed that with the progress of technology, OCTA will bring us a new chapter in the study of retinal vascular diseases including RVO.
Pachychoroidopathy is a type of retinal choroidal disease with similar clinical features, which is characterized by attenuation of the choriocapillaris overlying dilated choroidal veins, and associated with progressive retinal pigment epithelium dysfunction and neovascularization. At present, pachychoroidopathy includes pachychoroid pigment epitheliopathy, central serous chorioretinopathy pachychoroid neovasculopathy, polypoidal choroidal vasculopathy, focal choroidal excavationm, and peripapillary pachychoroid syndrom. These diseases not only have common imaging features, but also individual imaging features. This not only provides us with important clues about the pathogenesis of pachychoroidopathy, but also provides guidance for their treatment decisions. Although the exact pathogenesis of pachychoroidopathy is still unclear, and the treatment method is still controversial; but it is believed that with the development of imaging technology and the development of high-quality clinical and basic research, patients with pachychoroidopathy can be provided with more reasonable treatment in the future.
Autofluorescence is produced by lipofuscin in retinal pigment epithelium (RPE) cells which is induced by exciting light and enables the visualization of lipofuscin changes in the RPE cells, thus showing the function of RPE and photoreceptor cells. Fundus autofluorescence (FAF) imaging is a non-invasive imaging technique providing information of RPE and photoreceptor cells, which is not obtainable with other imaging modalities. The scope of applications includes identification of diseased RPE in retinal diseases, elucidating pathophysiological mechanisms, estimating disease progression and prognosis, guiding treatment protocols. Common fundus diseases have different pathological types, levels and causes, so they can cause various damages of RPE and photoreceptor cells which induce complicated FAF. It is worth to further observing and investigating the common retinal diseases' FAF characteristics and clinical applications.
Polypoidal choroidal vasculopathy (PCV) is a fundus disease characterized by choroidal anomalous branch vascular network and terminal polypoidal dilatation. According to its fundus feature, lesion location, imaging feature and disease progression, PCV can be divided into different types or stages. It can be divided into hemorrhage and exudation PCV according to the fundus features, into macular, peripapillary, periphery and mixed types according to the lesion locations. It can also be divided into type 1 and 2 according to the ICGA (indocyanine green angiography) manifestations, and can be classified as early stage and late stage according to disease progression. There were different correlations between different types of PCV and some risk genetic loci, such as ARMS2 (age-related macular degeneration factor 2)/ HTRA1 (high temperature essential protein A1) , C2, complement factor B, complement factor H, and elastin genes. The response to therapy and prognosis are also different between different types. It is important to further study the clinical classification of PCV, to explore the genetic characteristics, influencing factors and treatment or prognosis features of different types of PCV. The results will improve the differential diagnosis of PCV, and the effectiveness of individualized treatment.