Cardiovascular diseases can cause high intraocular pressure. The main cardiovascular diseases that cause elevated intraocular pressure are retinal vein occlusion and diabetic retinopathy. 1. Retinal vein obstruction: This includes the obstruction of the central vein or branch veins of the retina, which causes hypoxia of the eye (especially the posterior segment of the eye), interferes with the normal aqueous humor circulation, and results in the elevation of intraocular pressure (IOP), which is called neovascular glaucoma. 2. Diabetic retinopathy: It is the most common microvascular complication of diabetes mellitus, which leads to hemorrhagic foci in the retina, proliferative retinopathy, and possible neovascularization, which interferes with the normal atrial aqueous humor circulation, resulting in elevated intraocular pressure (IOP). Elevated intraocular pressure may be followed by eye pain, photophobia, corneal edema, and moderate to severe hemorrhagic manifestations. If symptoms are detected, early treatment is recommended.