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.