Dexamethasone, a potent corticosteroid, has been shown to suppress inflammation by inhibiting oedema, fibrin deposition, capillary leakage, and phagocytic migration of the inflammatory response. Vascular Endothelial Growth Factor (VEGF) is a cytokine which is expressed at increased concentrations in the setting of macular oedema. It is a potent promoter of vascular permeability. Corticosteroids have been shown to inhibit the expression of VEGF. Additionally, corticosteroids prevent the release of prostaglandins, some of which have been identified as mediators of cystoid macular oedema.
If there are a lot of flashes and floaters all of a sudden, the eye needs to be examined to check if there is a small tear in the retina. If a 'curtain' or 'shutter' drifts across the vision, an examination is needed the same day to check for a retinal detachment (this usually means attending an 'Emergency' Eye Department, such as that at Birmingham and Midland Eye Centre, City Hospital). In addition there are other very unusual complications.