Age related macular degeneration (AMD) is a major cause of legal blindness in elderly individuals in the western world. It affects the macula, initially with characteristic retinal pigment epithelium (RPE) changes (mottling, hyper/hypopigmentation) and drusen deposition (dry AMD). Of note is the presence of a series of inflammatory factors between the RPE and Bruch's membrane. The progression of AMD leads either to late stage geographic atrophy of the macular RPE, or to neovascularization (neovascular AMD), due to vascular endothelial growth factor (VEGF) production.
Neovascular AMD is the most vision-threatening form of the disease. Visual impairment in neovascular AMD is caused by the formation of a choroidal neovascular membrane (CNV) beneath the macula with consequent subretinal leakage, hemorrhage and intraretinal fluid accumulation. Inflammatory factors and VEGF are the main contributing mediators involved in the progression of AMD, participating in a vicious cycle involving hypoxia, oxidative stress, inflammation, edema and neoangiogenesis.
No comments:
Post a Comment