Vascular diseases of the brain affect vision owing to a variety of mechanisms and cause a range of signs and symptoms. These conditions may result from diminished blood flow, from leakage of blood through vessel walls, or from the compression of adjacent structures by enlarged vessels. Vascular disease may affect the arterial or venous systems and may be caused by abnormal communications between arteries and veins. In some cases, these visual manifestations have a significant impact on quality of life; in other cases, they may be warning signs of serious underlying neurologic or systemic disease. This article emphasizes the conditions that present most commonly to ophthalmologists.