VEGFA and macular retinal edema: If the retinal oxygen tension increases after PPV, macular edema would decrease for the following two reasons: 1) an increase of oxygen tension would reduce VEGF production and decrease vascular permeability to reduce edema, and 2) an increase of oxygen tension would alleviate autoregulatory arteriolar vasoconstriction and thus lower the hydrostatic pressure in the retinal capillaries and venules, so that decreased water flux from the vascular compartment to the tissue compartment would reduce edema according to Starling’s law.