Pathophysiology and classification of diabetic retinopathy and maculopathy

Diabetic retinopathy develops in a sequence of three interactive reactive mechanisms: Firstly, pathobiochemical reactions take place in response to chronic hyperglycemia which influence the balance between growth factors and can lead to morphologically appreciable vessel damage in non-proliferative diabetic retinopathy and diabetic maculopathy. Pathologically increased vessel permeability, as well as increased retinal hypoxy form hemodynamically. Once a certain degree of retinal ischemia is reached, the balance between growth-inhibiting and -stimulating factors is irreversibly disrupted. This results in proliferative diabetic retinopathy with retinal vessel neoplasms, which in turn can lead to vitreous body hemorrhage and traction-related retinal detachment, as well as neovascularization of the iris with secondary glaucoma and thus to advanced diabetic ocular disease.