Hypertensive retinopathy. Opthalmoscope view of the retina of the eye in a patient suffering from hypertension. Hypertension is the elevation of arterial blood pressure. Here, it has affected the blood vessels of the retina causing the arterioles (lighter in appearance) to dilate and compress the veins which lie beneath them as seen at sites of arteriovenous crossing. At right is the yellow optic disc. Abnormally high blood pressure in hypertension may also produce white cotton wool" exudates on the retina (proteins and white cells that have oozed through intact blood vessels), or there may be blood haemorrhage. Treatment usually involves drug therapy to lower blood pressure."