With the tremendous progress in fundus imaging and histopathology over the past decade, the understanding of age-related macular degeneration (AMD) has taken a qualitative leap. AMD is defined as a progressive neurodegenerative disease of photoreceptors and retinal pigment epithelium (RPE) characterized by extracellular deposits under RPE and the retina, including drusen, basal laminar and linear deposits, and subretinal drusenoid deposits, that can evolve to atrophy of the retina, RPE and choroid and neovascularization in the choroid and/or retina. It is the leading cause of blindness and visual impairment in older populations, despite recent advances in treatments. AMD is a multifactorial disease with genetic and environmental factors including advanced age, smoking, high-fat diet, and cardiovascular disorder to enhance the disease susceptibility. The physiopathologic mechanism includes inflammatory processes (complement pathway dysregulation, inflammasome activation), intrinsic (e.g., photo-oxidation) and extrinsic oxidative insult to the retina, age-related metabolic impairment (mitochondrial, autophagic and endoplasmic reticulum stress). Autophagy dysfunction and local inflammation in aged RPE specially result in the extracellular deposits, cell death and AMD. Further investigation of the pathogenesis of AMD will provide with new therapeutic targets and strategy for prevention and treatment of the disease in the early stages.
Complications of proliferative diabetic retinopathy have become the major indications of vitrectomy. The surgery, however, is not basically a causative therapy. The visual function after operation depends on the degree of retinal ischemia and damage induced. The surgery itself has a potential for severe complications. Therefore it is important to better understand the pathology and to master surgical strategy and techniques in order to improve surgical outcomes and reduce the surgical complications. (Chin J Ocul Fundus Dis,2007,231-233)
Diabetic retinopathy (DR) is the leading cause of visual impairment worldwide. Severe non-proliferative diabetic retinopathy, diabetic macular edema, and proliferative DR (PDR) are defined as vision-threatening DR (VTDR). In the context of managing systemic disease, the primary treatments for VTDR include panretinal photocoagulation (PRP), intravitreal injection of anti-vascular endothelial growth factor (VEGF) drugs or dexamethasone sustained release agents, and microincision vitreous surgery. Although these therapies are already widely used in clinical practice, there is still much debate about the optimal timing and method of their application, especially in the pursuit of optimal efficacy, cost-effectiveness, patient compliance, and the reduction of frequent ongoing treatments. There is no consensus on the best treatment for PDR. Determining the specific criteria for each therapy indication is one of the key considerations. In addition, consideration should be given to the priority between PRP and intravitreal injection, as well as to compare the relative effectiveness of anti-VEGF agents with PRP. Early surgical intervention is not always a necessary option for PDR patients with vitreous hemorrhage and fibrovascular membranes. Combining different therapies to optimize treatment strategies is also an important topic. These issues address several points of contention in best practice guidelines that need to be addressed through more in-depth research to provide better guidance for clinical practice and ultimately improve patient outcomes.