Diabetic maculopathies.

Pathological changes in the diabetic macula are a frequent cause of visual loss. They can be classified as intraretinal or vitreoretinal maculopathies. The intraretinal ones are due to hyperpermeable retinal capillaries or retinal vascular shut-down. They appear clinically as macular edema, exudative maculopathy, fluorescein dye leak maculopathy, or ischemic maculopathy. When edema and exudation cause or threaten to cause significant visual loss they are treated by photocoagulation. The vitreoretinal maculopathies are due to traction resulting from (1) the formation of vitreoretinal adhesions with subsequent vitreous shrinkage, (2) the formation of bands or membranes from one retinal area to another and their subsequent shrinkage, or (3) epiretinal membrane formation and contraction. They appear clinically as epiretinal membranes, retinal wrinkling, macular heterotopia, or traction detachment of the macula. Traction detachment and contracted epiretinal membranes associated with significant visual loss are treated by vitreous surgery; an effective treatment for macular heterotopia has not been demonstrated.