Contributor: Gordon K. Klintworth
Hypertensive retinopathy is a common disease of the retina. Severe hypertension commonly affects the retina and causes hypertensive retinopathy. Hypertensive retinopathy is associated with retinal arteriolosclerosis. Abnormalities readily seen with the ophthalmoscope relate to the severity of the hypertension. Based on its severity hypertensive retinopathy can be classified into Grade 1 to Grade 4. Grade 4 has most serious changes and a poor prognosis. 
Features of hypertensive retinopathy include focal vasospasm, variable degrees of retinal arteriolosclerosis, flame-shaped hemorrhages, cotton wool spots and microaneurysms. In severe hypertension, the retinal arteriolosclerosis is more marked, and exudative retinal detachment [retinal detachment - exudative] and papilledema ensue. Papilledema is a clinical marker for malignant hypertension and impending hypertensive encephalopathy. Elschnig spots and Seegrist streaks are found in some patients with malignant hypertension. Retinal arteriolar narrowing and focal vasospasm is caused by acute, severe elevations of the blood pressure. Prolonged persistent vasospasm produces necrosis of retinal muscular and endothelial cells. Vascular incompetence caused by endothelial damage leads to hemorrhage, exudation, retinal edema and even exudative serous retinal detachment. Arteriolosclerosis of the retinal and choroidal arterioles is common.
In malignant hypertension [hypertension - malignant], a necrotizing arteriolitis [arteriolitis - necrotizing], with fibrinoid necrosis and thrombosis of the precapillary retinal and choroidal arterioles occurs and the retinal exudates often encicle a macular star. In severe hypertension discloses endothelial degeneration, necrosis of vascular smooth muscle and insudation of fibrin-rich plasma in the vessel wall.