The most common cause of Macular edema is

Macular edema refers to the collection of fluid in the outer plexiform(Henle's layer) and an inner nuclear layer of the retina, centered around the foveola.EtiologyIt is associated with a number of disorders. A few common causes are as follows:1. As postoperative complication following cataract extraction and penetrating keratoplasty.2. Retinal vascular disorders e.g., diabetic retinopathy and central retinal vein occlusion.3. Intraocular inflammations e.g., pars planitis, posterior uveitis, Behcet disease.4. As a side-effect of drugs e.g., following use of adrenaline eyedrops, especially for aphakic glaucoma.5. Retinal dystrophies e.g., retinitis pigmentosa.Ref: Khurana; 4th edition; Pg.No. 273