Because 3-[(3S,4R)-3-Methyl-6-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)-1,6 -diazaspiro[3.4]octan-1-yl]-3-oxopropanenitrile suppresses an increase of the retinal vascular permeability induced by VEGF, it can be used as an active ingredient of a therapeutic or preventive agent for various eye diseases involving VEGF, such as age-related macular degeneration, diabetic retinopathy, macular edema, neovascular maculopathy, retinal vein occlusion and neovascular glaucoma.
